Glass or Rock?

Rock crystal ewer, Egypt (1000-1050)
V&A Museum, #7904-1862

Today, a sharp distinction is made between glass and rock, but in the early seventeenth century, differences in the two materials were not so well defined. One was the product of nature and the other of art, but after that the lines begin to blur. Philosophers debated weather glass should be classified as artificial stone, and why not? It is a material that was actually made from crushed up rocks (quartz and calcined limestone) with the addition of plant salts. In a very accurate sense, it is a form of artificial rock. 

In his 1612 book L'Arte Vetraria, Florentine glassmaker Antonio Neri repeatedly illustrates the thinking that glass was an artificial form of rock. The very first part of the book concerns itself with cristallo glass, which was considered to be an imitation of natural rock crystal. He devotes a whole section to the imitation of the colorful stones variously known as chalcedony, jasper and oriental agate. About these he writes: 

It is often said, and it may well seem to be true, that art cannot match nature. However, experience in many things shows, and this is particularly true of colors in glass, that art not only challenges and matches nature, but by far exceeds and surpasses it. Why, if you did not see it for yourself, you would find it hard to believe the beauty and great variety of interplay seen in these particular chalcedonies.

Another entire section of the book is devoted to artificial gemstones: rubies, sapphires, emeralds, topaz, chrysolite; he even uses crushed natural gems to color his glass. He describes a "sky blue even more beautiful, from the garnets of Bohemia." 

An earlier 1540 book that Neri read closely was by Italian metallurgist Vannoccio Biringuccio, called De La Pirotechnia. This was the first book entirely devoted to mining and metal foundry practices. Biringuccio was from Siena, but was considered something of a folk hero in Neri’s nearby Florence because he oversaw the casting of iron cannons for the city's defense in the great siege of 1529–30. His book contains a short six-page chapter devoted to glass where he writes:

[I]t [glass] is one of the effects and real fruits of the art of fire, because every product found in the interior of the earth is either stone, metal or one of the semi-minerals. Glass is seen to resemble all of them, although in all respects it depends on art.

This is an observation that Neri echoes almost verbatim in the introduction of his own book, and in this light, it is not so difficult to see what connects glassmaking to alchemy. Neri was in the business of learning nature's secrets, and then using them to create new materials that were even better than the originals. These are aims quite familiar to any modern materials engineer. Neri and his contemporaries were successful up to a point. They were able to create artificial gems and other items that were impressive in color and clarity, yet they lacked some key properties of their natural counterparts, most notably hardness. 

Based on Neri's earliest known writing Treasure of the World, started in 1598, he was already familiar with mining practices before his glassmaking activities started and over a decade before he would write the book. He devotes this early manuscript to "all of alchemy, its furnaces, instruments and the mining of metals." Around 1600 he started work at Prince Don Antonio de' Medici's Casino di San Marco laboratory. Here, he may have had the opportunity to interact with characters such as Filippo Talducci (1543- c.1615), celebrated Florentine chemist and mining engineer, several of whose relatives worked at the Casino. In his 1613 manuscript Discorso, Neri strongly hints that he has personally been to more than one mine in connection with his alchemical activities. "I would not say this, had I myself not had the good fortune of being in such a mine from which, with much artifice, was extracted a small quantity of real gold liquor, which was the true golden seed. […] To this day I have never found another mine like it, and therefore suitable for this purpose." 

Today, we hardly associate glass with the raw materials from which it is composed, just as we hardly ever think of metals in their unrefined state. Antonio Neri was more closely connected to the earth, by virtue of his profession, but also because daily life in the early seventeenth century was filled with such activity; refining raw materials into useful forms had a direct and immediate impact on quality of life. Although glass is now manufactured in highly automated facilities, far away from our daily lives, it is still essentially the same product that Neri made. The next time you come in contact with a piece of glass, to pour a drink or look through a window or read the text on a screen as you are probably doing right now, stop for a minute and think of it as Neri did four centuries ago, as artificial rock.

Telling Time

The face of the clock at S.M Fiore in Florence,
Painted by Paolo Uccello (1443).

In his 1612 book on glassmaking, many of Antonio Neri's recipes depend on timing. In two recipes, he uses recitation as his method. "Mix this tartar with the sifted kermes, and when the water in the kettle boils, put in all the kermes, and let it dye the water, reciting the Miserere Psalm once." (ch. 117.) The 50th (51st) psalm begins "Miserere mei, Deus..." (Have mercy upon me, oh God...). Assuming he was using the Vulgate version adopted by Clement VIII in 1592, recital takes about 2 minutes 15 seconds without rushing. "Mix the powders, and always give them to the glass in six portions, stirring the glass well. Set the interval from one portion to the next by reciting the [Apostles'] Creed." (ch. 65.) There are shorter versions, but assuming he used the creed of Pius IV, adopted at the council of Trent in 1564; recitation takes a little under 3 minutes.

There are dozens of other instances where Neri calls for periods in time ranging from hours to days to months. In several cases he specifies the duration of a half-hour, implying the use of a clock or timer of some kind. So, it is worth taking a closer look at exactly how timekeeping worked in his era. In the early seventeenth century, water clocks and hourglasses were long common, and small spring driven mechanical clocks were becoming fashionable, although very few have survived until today. Judging by the unusual precision of birth times in the baptism entries for Antonio and his siblings, it seems likely that the family owned an accurate clock. For example, his own birth is recorded as 29 February, at 3 hours 25 minutes past sunset. This level of accuracy in the matter of birth was sometimes employed in anticipation of better astrological charts.

It was common for a European town to have a public clock in their city hall or principal church; Neri’s home town of Florence, Italy, had both. In 1353, Nicolò di Bernardo built the city's first public clock for the Palazzo Vecchio. (It was replaced by a German clock in 1667, which is still there today). In 1443, Angelo Niccolai degli Orologi, (a grandson of the above Nicolò) built a second municipal clock, this one for Santa Maria del Fiore, installed inside the cathedral above the main doors. Compared to modern clocks, this one has some unusual features: The single hand runs counterclockwise, mimicking the motion of the shadow on a sundial. The twenty four hour mark makes its appearance at the bottom of the dial. (The actual clock mechanism was replaced in 1761 by Giuseppe Bargiacchi, but keeps time identically).

These clocks were built after the invention of the escapement (the part that goes tick-tick, tick-tock), but before pendulums had been incorporated. Galileo realized the advantages of pendulums in timekeeping during our glassmaker Neri’s lifetime, although they were not acted upon for another half-century. The accuracy of any clock depended on the ability of its mechanism to keep a steady pace, and in the early seventeenth century, a fifteen minute error was not uncommon. The clocks at the Palazzo Vecchio and Santa Maria del Fiore were checked regularly and adjusted based on the readings of a nearby sundial, so the time also shifted with the seasons. 

In Florence, and many other Italian cities, the custom was to start counting hours at sunset. Each day was divided into twenty-four equal hours. The start of the Church’s liturgical day was actually signaled a half hour after sunset with the ringing of the bells for the Ave Maria prayer during evening Vespers service. One o’clock was one hour past sunset, etc. This first hour was called "l’or di notte," [the night hour] and contrary to what one might think, it did not signal the beginning of a new calendar day. Each new day began with the ringing of the Campanile bells at sunrise. This Italian system of timekeeping (hora itálica) had been practiced for over a millennium, it was established by Julius Caesar for the Roman Empire. Not until 1750 did Italians adopted the current (French) system of two twelve hour shifts beginning at midnight.

Cristallo

Dragon-stem goblet, Venice, Italy,
(or in the Venetian style), 17th cent.
Corning Museum of Glass 51.3.118.

Venetian cristallo is quite literally the glass that made Murano famous. Ultimately, royal courts and wealthy families throughout Europe coveted glassware of this type. It had the clarity of its namesake mineral, rock crystal, and its working properties were such that one could make extremely thin, yet complex pieces. At a time when glass made from dirty sand and fireplace ash was churned out cheaply and quickly around Europe, cristallo was the absolute pinnacle of the glassmaker's art.

Murano glassmaker Angelo Barovier gets credit for the development of cristallo around the year 1450. However, it is a mistake to think that suddenly, he exclaimed "eureka" and burst out of his workshop with an entirely new invention. The predecessor of cristallo was what Antonio Neri called cristallino, which already incorporated some of the advantages. Barovier may well be responsible for bringing together the ultimate refinements that elevated cristallino to a new level of perfection, but these techniques individually were all available and utilized by glassmakers at least fifty years earlier. 

Barovier had attended lectures by noted alchemist Paola de Pergola, at the School of Rialto. This indicates that he was thinking along the lines of a chemist in putting together a repeatable regimen for an exceptionally clear, bright, workable product. The real genius in cristallo was in controlling the purity and quality of all the materials through Venice's extensive trade network in the Mediterranean. Even if the recipe leaked out, exclusive trade agreements blocked access to the raw materials. Local ordinances tightly controlled source materials used in the furnaces to ensure consistency, from the quartz river pebbles crushed for frit, to the plants used to make the flux, to the manganese which eliminated any slight tinting. Requirements even stipulated the making of the furnace crucibles from a specific variety of clay from Constantinople.

Barovier's innovation would become a tradition that would be carried on by countless glassmakers and ultimately by our Florentine priest, Antonio Neri, more than a century and a half later. Neri describes the Venetian methods, but then goes on to innovate with variations of his own. Numerous family manuscripts in Venice documented the method to make cristallo; what Neri did was to publish these relatively secret techniques and make them available to anyone who could read his book, and many did. 

For silica, the main ingredient in glass, Neri says the craftsmen on Murano specifically used quartz river pebbles (tarso) from the Ticino River in Pavia. He describes special procedures to pulverize the stones without contamination, into a powder "ground as finely as flour." Next, he makes the flux (glass salt), which allows the quartz to melt at lower temperatures. He says to use the ash of the kali plant from Syria (polverino and rocchetta). This plant ash is very rich in sodium carbonates; he extracts and purifies it in a process called lixiviation. Neri purchased the starting material in a charred state, which reduces it weight and volume for shipping. From 300 pounds of ash, he usually produced 80-90 pounds of salt. The ash was boiled in cauldrons full of water, strained, filtered, evaporated and dried leaving the all important glass salt. Into each cauldron, he mixes ten pounds of tartar—the dried dregs scraped from the inside of red wine barrels—a material high in potassium carbonates. Today, we know the soda component is responsible for the favorable property of long working times for artisans before the hot glass stiffens, the potassium adds sparkle. The final ingredient was two pounds of lime (calcium oxide) per one hundred pounds of salt, which is added to the dry salt because it is not water soluble. This stabilized the glass against future degradation by moisture over time. 

200 pounds of powdered quartz mixed thoroughly with 130 pounds of the salt forms the basis of the frit. He raked the powder around in a hot kiln for about five hours, until "nut sized" pieces began to form. Now this cristallo frit,—which Neri calls bollito—was carefully packed to remain dry and allowed to age for three or four months, when it was ready to melt in the furnace. If the glass should have a slight green tint from iron tools, it was corrected with manganese (oxide), specifically mined in the Piedmont region. The cristallo was boiled for up to six days and repeatedly washed by ladeling the hot glass into cold water and then remelting.

The result was a glass that was a pleasure for gaffers to work and make finished pieces over which royalty clamored. Cristallo was uniform in consistency, it could be blown into molds or worked freehand into complex shapes, like the iconic "dragon goblet" form, which became a hallmark of the Venetian masters.

Gold Ruby Redux

A gold florin.
Legend claims gold ruby glass
 was discovered when a nobel threw
a gold coin into a glass maker's crucible.

Antonio Neri is best remembered for writing L'Arte Vetraria. It was the first printed book entirely devoted to the formulation of glass, which he published in Florence, Italy, in 1612. If we were to single out just one of his more than a hundred recipes, covering glass, lead crystal, paste gems and enamels, it would have to be his prescription for "Transparent Red" ruby glass made with gold. This recipe still captivates glass artists today, as it has since Neri wrote the book. In fact, gold ruby glass is closely tied to the lore of alchemy and has intrigued experimenters as well as artists and collectors since the Roman Empire, possibly before.

Alchemists had long thought gold to be the perfect metal and that all other "lesser" metals (read: lead, tin, copper, iron, mercury and silver) could be coaxed to fully "mature" into gold. Experimenters thought that if they could capture the "essence" of the king of metals, it could be used to "seed" the other metals, and transmute them into pure gold. This is where ruby glass comes into the discussion. In general, glass is colored by the addition of finely powdered metals. Depending on the metal and how it is treated, a whole rainbow of colors can be produced in glass. Alchemists were convinced that the color was an indication that this "essence" of the metal had been released into the glass. 

For artists and collectors, gold ruby is simply a very attractive color; the difficulty of producing it and working with it only adds to its cachet. Transparent red in glass can be produced other ways, notably with copper, but copper red has a slightly more orange color. Gold ruby, on the other hand, has a characteristic red color that can have slight hints of purple. It can be made light and ethereal or dark and heavily saturated, but viewed next to its competitors, it has a very distinctive hue that experts pride themselves on recognizing.

Neri’s recipe involves moistening gold powder with "aqua regia," which we know as a mixture of nitric and hydrochloric acids. He then spreads this wet mixture on an earthenware pan and heats it in the furnace "until it becomes a red powder, which will take place after many days." Here is that color change that alchemists looked for as an indication of transformation; we know today that Neri was producing gold chloride. This is one of the very few chemical compounds that gold forms and in fact, this is one of the main things that makes gold so special: it does not rust, nor corrode or tarnish, which are, in the end, all chemical reactions between the metal and its environment.

Neri directs his readers to sprinkle, little by little, the gold chloride into the glass melt. He says to "Use fine cristallo, thrown in water many times." Cristallo is the exceptionally clear glass invented by Venetian craftsmen, and "washing" was a technique to remove excess water soluble flux and other contaminants. He finishes his instructions abruptly by saying this method "will make the transparent ruby red glass; but you must experiment in order to find it." In other recipes, Neri goes to great lengths to explain his methods in detail, here he seems content to barely scratch the surface. Much speculation has taken place over the reason for this surprisingly short recipe. Was he ordered, perhaps by his Medici overlords, to keep details to a minimum? Some have wondered if Neri even knew how to produce gold ruby; the short recipe may have been a cover for his lack of knowledge.

Doubts about Neri's gold ruby glass recipe grew after his death, when it was discovered by other experimenters that the addition of small amounts of tin into the mix produced the ruby color quickly and reliably. This compound of tin and gold chloride was called "Cassius purple" after one of its inventors and its color. In some circles it was thought that the tin was an essential ingredient, a lost secret that had been rediscovered. The argument was that gold chloride alone could not produce the color, it must be combined with tin in the form of Cassius purple. However, this is not the case. 

In an 1846 edition of the Journal of the Franklin Institute (ser. 3, v. 11), professor of chemistry and natural philosophy, E. L. Schubarth, cites numerous investigators who demolish this theory. He wrote:

It must not be imagined from this, as some persons have lately stated, that it is necessary to use gold [combined with tin] in the state of Cassius purple.

Neri, at the end of the sixteenth and commencement of the seventeenth century, stated, that in order to stain glass a ruby color, it was only necessary to employ calcined chloride of gold. At a later period, Libar wrote to the same effect, and Merret certified that he had proved the efficacy of the process. In 1834 Golfier Besseyre stated, in the Journal of Pharmacy, that Douault Wieland colored his paste with perchloride of gold only. Lastly, in 1836, Fuss writes, that in Bohemia all the ruby-colored glass was prepared with chloride of gold only, and that glass might be stained red as well with metallic gold, as with oxide of gold or Cassius purple.

It is therefore a fact known for some time, that glass may be stained red, without either Cassius purple or oxide of tin, with [only] metallic gold or preparations of gold. In the glass-works of Bohemia and Silesia perchloride of gold only is used, without the addition of oxide of tin, in order to produce their fine rose or carmine-colored glass.

Of the men cited, Douault-Wieland was a Parisian jeweler who was famous for his artificial gems and crystal glassware. He was praised for his skills by Napoleon. Paul Golfier-Besseyre was a well respected French chemist. Besides many other endeavors, he worked for the glass industry and performed numerous experiments on the formulation of glass. He produced a gold ruby using the same ingredients as Neri. He determined good color could be achieved by letting a new batch of the glass age for a protracted period of time at temperatures below the melting point of gold. Periodically, he removed the glass from the furnace and poured it into water to wash it. The result was a yellowish glass when molten, but when a gaffer finished a piece it was gently reheated and the ruby color developed. 

The Golden Nail

Portrait of Leonhard Thurneysser
Frans Floris de Vriendt (1519/20 - 1570)

Of all the stories of transmutation by alchemists, one of the most interesting is the story of the "golden nail" in which Ferdinando de' Medici witnessed, with his own eyes, a demonstration that purported to turn half of a common iron nail into pure gold. The nail in question became a treasured possession of Ferdinando and was displayed for many years at the Galleria dei Lavori, in the Uffizi palace, in Florence. 

It is all but certain that glassmaker and alchemist Antonio Neri saw the nail, probably many times in his career. In his 1613 manuscript Discorso he says:

Some argue that the possibilities of this art are demonstrated clearly through the experience of the 'nail' [chiodo], which is seen in the Galleria [dei Lavori] of the grand duke of Tuscany, of which one part is solid iron and the other which was immersed in some sort of liquor is recognized to be pure gold.

It is interesting that Neri does not commit here, to the conviction that this "is" transmutation, only that "some argue the possibilities." The story was recounted by numerous chroniclers and became a favorite subject of speculation. Was this a case of a cleaver deception? A century later, it was still being talked about: here is Otto Tachenius, in his Hippocrates Chymicus (1677) quoting then Cardinal, later Grand Duke Ferdinando I de' Medici. 

Mr. Leonhard Thurneysser in my sight and presence, turned an iron nail heated in the fire, and immersed in an oil, into gold; done at Rome the 20th day of November after dinner.

So it would seem that at least the Grand Duke was convinced.

Thurneysser was the son of a goldsmith from Basel, and a devotee to the methods of Paracelsus. He became intrigued with alchemy and made a fortune touring the courts of Europe, putting on demonstrations. When Antonio Neri was about fourteen years old, cir.1590, Thurneysser passed through Florence.* In later testimony by Neri associate Guido Melani, a metals refiner, the priest had confided in him that he himself had learned a gold transmutation recipe from a German, who used the techniques of Paraselsus. It is conceivable that this was Thurneysser. 

Skeptics proposed a very plausible explanation: that a special nail was prepared in advance, half gold soldered to half iron. The entire nail was then recoated with a thin layer of iron, perhaps deposited chemically. In the demonstration, the special nail would find its way into Thurneysser's hand, and with great flourish be heated and then dipped into the secret oil, which was aqua fortis, what we know today as nitric acid. The iron coating on the nail would fizzle and sputter in the acid and dissolve away to reveal the pure gold interior.

Those calling themselves "alchemist" ran the gamut from small time confidence men right through to early modern scientists and everything in between. To complicate things further, when they were found in the same room together, the scientist might not be so motivated to unmask the huckster. Thurneysser's demonstration clearly fired Grand Duke Ferdinando's imagination, and may well have influenced him to make a place at court for Antonio Neri.

* UPDATE: 24 Feb 2014, recent scholarship has cast serious doubt that Thurneysser was ever in Florence. This makes a meeting with Neri unlikely. I hope to make this the subject of a future blog post – stay tuned.

The Duke’s Oil

Trajan's Column, Rome
Giovanni Battista Piranesi (1758)

In the seventeenth century, alchemy was a dangerous business. Yes, there were risks of sanctions by the authorities, which could be very harsh, but great dangers also lurked in the chemicals themselves. Some like lead and mercury accumulated in the tissues slowly, over a period of years, others could kill a man within a few minutes. Cardinal Francesco Maria del Monte had personal knowledge of just how deadly the products of alchemy could be.

In Rome, Del Monte was the unofficial ambassador to Florence and the Medici family. He regularly greeted dignitaries from around Europe and dazzled them in his sumptuous palace. He was an avid glass collector, a patron of the arts and more quietly a dedicated student of alchemy. He was a lifelong friend to Don Antonio de' Medici and visited the prince's laboratory in Florence several times. This is where Antonio Neri was making glass early in his career. Later, Neri worked at a secondary Medici glass furnace in Pisa, where the cardinal had fancy glass table service made for the Vatican.

About a two mile walk from Saint Peter's Basilica, over the Tiber River, directly toward the Colosseum, is Trajan's Column. It commemorates Emperor Trajan's victory in the Dacian Wars at the beginning of the second century. It displays a scroll in base relief that winds all the way from the pedestal to the capital. The monument is large enough to contain an internal staircase leading to an observation platform at the top. In 1587, it was crowned by a bronze statue of Saint Peter that still stands today; the initial model was sculpted by artist Tommaso della Porta, who was under the patronage of Cardinal Del Monte. 

Giovanni Baglione picks up the story in his book Lives of Painters, Sculptors and Architects:

That man [della Porta], I think, suffered mentally and it showed at the end of his days. When he felt some kind of tingling in his abdomen, he went to the Cardinal del Monte his friend and master and asked for some of the "grand duke’s oil" that he hoped would relieve the tingling. The Cardinal indulged him; gave it to him and said that he should apply it only to the wrists and only a little, because the oil was potent and it could make him feel sick. He took it and went back to his house and after dinner he sent for the barber, to administer the medication, and while the messenger went on, Tommaso impatient and simpleminded, applied the oil himself and instead of touching the wrists, as the Cardinal had instructed, he lathered the arms, chest, body and entire abdomen, so that the powerful oil went to the heart and in fact killed him. The barber arrived to medicate him, found him dead and all attempts at revival were in vain. Tommaso della Porta, was buried at Santa Maria del Popolo.

The "grand duke's oil," was widely known, and widely cited in references throughout Europe well into the 19th century. Its other name was oil of tobacco – essentially a distillation of almost pure nicotine. In very small doses, it acts as a stimulant of the central nervous system, in slightly higher doses it is a narcotic, even greater, but still relatively small amounts act as a quick and lethal poison absorbed directly through the skin. Ingesting a single pill capsule of typical size full of pure liquid nicotine is more than enough to kill an adult in short order.

This story has one final twist. Antiques dealer Domenico Lupo was one of the men present at the reading of Della Porta's will on 7 March 1607. Twenty-five years later, an inventory of Lupo's assets listed a "small figure half old and half new that is said to be of Prior Ant. Neri," either the glassmaker or possibly his great uncle.  

Saint Philip Neri

Saint Philip Neri

In the final quarter of the seventeenth century, a certain holy man in Rome practiced charity in its humblest form. A native of Florence, a man named Filippo Neri (1515-1595) made visits every day to plague victims in the hospitals. He prayed for patients in their last hours and brought food for those abandoned by their families. He walked among the poor and destitute, eating just from the alms he received. He lived what he preached and set an example of Christianity stripped of pride and envy. In unconventional style, he led walking tours of the churches in Rome. Although the practice of venerating the living as saints received strong discouragement by the Church, Filippo Neri nevertheless realized effective sainthood during his lifetime. His followers credited him with numerous miracles. 

Conventional history places the exact location of Filippo Neri's birth in Florence on the south side of the Arno. However, local folklore suggests an alternate location: in one of two rooms of the same Borgo Pinti house later owned and occupied by Antonio Neri's family. The common family name of Neri naturally leads to the question of whether or not the saint and the glassmaker were of common ancestry. Antonio's father, Neri Neri, maintained that his own father, Jacopo, was a cousin to the holy man. 

A full-length image of Filippo Neri himself appears in a corner of the Neri chapel, On Borgo Pinti in Florence. Giovanni Cinelli, writing in 1677, tells us of Neri di Jacopo (Neri Neri):

It was his intention to dedicate [the chapel] to his relative Filippo Neri; it is possible that Jacopo di Neri, father of M[esser] Neri Neri was the cousin of Filippo Neri then still living, today Saint Philip. But [the dedication] was not to be, because in pressing to oversee its completion and delays in the canonization of the Saint, the dedication was changed to Nereo and Achilles, which was finished by Alessandro per the will.

Because the canonization was delayed, it would have been inappropriate to dedicate the chapel to Filippo, so two of his favorite saints were substituted.

The assertion that Neri the medical doctor and Neri the holy man were true blood relations has yet to be verified. However, there are positive signs: the saint's well-established genealogy meshes with records of Antonio Neri's family housed at the state archives in Florence. In fact, both sets of records—of the alchemist and of the saint—share a single file in the archives. These documents indicate a common ancestry at the level of third cousins. The elder Jacopo Neri and Filippo Neri (later Saint Philip) appear to have shared a great-great-grandfather. It is a remote connection, but one that was a source of  pride for Antonio’s father. 

There is also a notable similarity of family crests; the shield of Saint Philip Neri's family feature three stars on a blue field, that of Antonio Neri's family features  a  banner with three stars against a blue rampant lion. The Saint's genealogy is well established, but the matter is complicated in that Antonio's branch of the family left Florence around the turn of the sixteenth century. Here we lose track of them for one generation. Regardless of the difficulties, there is mounting evidence that Antonio's fourth-great-grandfather, Michele di Neri, was the brother of Saint Philip's second-great grandfather Ser Giovanni di Neri. A further association with Filippo Neri lies with Antonio Neri's maternal grandfather, Francesco Parenti, who served as attorney for the saint’s sister Caterina in the execution of the holy man's will.

Filippo Neri was unusual for his time. He was a champion of the common man, and he was humble to a fault; not a leader by force, by wealth, nor by charisma, but by gravitas. Antonio Neri's father seems to have been a man from the same mold, as exemplified by the absence of self-import declarations or artifice. He admired Filippo Neri, and we can guess that he shared the holy man's philosophy. Filippo never wanted  and protested strenuously against any aggrandizement. We see this trait follow through with Antonio. In his manuscripts and in the book on glassmaking, there is no evidence of boasting, or name-dropping, nor claim of superiority. What we see is a humble quest to understand nature, and to be of service to mankind.