Who Invented the Mechanical Clock?

In researching the previous post, I came across a reference to Pope Sylvester II (formerly Gerbert d'Aurillac, c.946 - 1003) inventing the mechanical clock. The source of this was the William Godwin's final book, Lives of the Necromancers, An Account of the Most Eminent Persons in Successive Ages Who Have Claimed for Themselves, or to Whom Has Been Imputed by Others, The Exercise of Magical Powers [1834]:

This generous adventurer, prompted by an insatiable thirst for information, is said to have secretly withdrawn himself from his monastery of Fleury in Burgundy, and to have spent several years among the Saracens of Cordova. Here be acquired a knowledge of the language and learning of the Arabians, particularly of their astronomy, geometry and arithmetic; and he is understood to have been the first that imparted to the north and west of Europe a knowledge of the Arabic numerals, a science which at first sight might be despised for its simplicity, but which in its consequences is no inconsiderable instrument in subtilising the powers of human intellect. He likewise introduced the use of clocks. He is also represented to have made an extraordinary proficiency in the art of magic; and among other things...

The italics are mine. A little further along, Godwin adds a footnote that tells us his information comes from William of Malmesbury. William (c.1095 - c.1143) was the foremost English historian of the 12th century. Not exactly a contemporary, but maybe near enough that the memories and stories were still fresh? It would be difficult to determine the accuracy of this report, especially in the context of a brief blog post. Fortunately, I don't have to.

As it turns out, Marek Otisk of the University of Ostrava (Czechoslovakia) published an article on this very topic in September 2020, Gerbert of Aurillac (Pope Sylvester II) as a Clockmaker. He examines the reports from William of Malmesbury, the Chronicle of Thietmar of Merseburg (died c.1018), and a much later record (someone who died in 1610). Among his detailed examination of these and other historical records we learn that although William claims Gerbert built a clock in Reims, a friend of Gerbert's (Richest of Reims), writes about Gerbert's stay in Reims in detail and never mentions a clock. Otisk concludes that William's ascribing of the creation of a clock to Gerbert cannot be trusted.

The later report by the Benedictine monk Arnold Wion, who died about 1610, claims Gerbert built a clepsydra, a water clock, in Ravenna. What we know of Gerber's time in Ravenna, however, is that it was very short; again, no contemporary accounts support this story.

Thietmar of Merseburg tells a different story, that Gerbert created a clock in Magdeburg. Thietmar was a bishop and close friend of Holy Roman Emperor Henry II, who succeeded Otto III, credited with making Gerbert into Pope Sylvester II. Thietmar's Chronicle includes a specific detail about Gerbert creating, in Magdeburg, "created clocks (horologium) which he correctly calibrated according to the Polar star (stella, dux nautarum) which he observed through an observation tube (fistula)." [Otisk, p.32] Otisk likes this account because both Thietmar and Gerbert were in Magdeburg in the late 990s, and very likely crossed paths several times.

The use of the word horologium is misleading, however. We use it for the word "clock," but it is more likely that Gerbert was creating a calibrated armillary, or possible even an astrolabe, which he knew about from his exposure to science being done by Islamic philosophers.

So I can't tell you who created the first mechanical clock. But the question of horologium remains: when long-ago writers refer to "clocks," what exactly did they mean? What constituted a clock? There were several ways to measure time without staring at the sun and judging, and I'll talk about those devices tomorrow.

Armillary Spheres

The "wooden terrestrial spheres" mentioned here are what we now call "armillary spheres." An armillary is a spherical arrangement of rings designed to mimic the orbits of the sun and planets around the Earth—or around the Sun, depending on the prevailing theory at the time. If the Earth is the center, it is a Ptolemaic sphere; if the Sun is at the center, it is a Copernican sphere. China and Greece each invented them BCE. Hipparchus credited Eratosthenes (276 - 194BCE) as the inventor.

An early Christian philosopher, John Philoponus, wrote the earliest extant treatise on the armillary sphere and the astrolabe. The oldest example of one we have today dates to the 11th century.

Gerbert d'Aurillac (946 - 1003), who became Pope Sylvester II in 999, had brought the armillary sphere to Western Europe. He was also responsible for introducing Western Europe to the abacus, the Hindu-Arabic numeral system we use today, and (possibly) the mechanical clock.

Sylvester used the armillary sphere and sighting tubes to determine the definitive position of the pole star and to record measurements for the tropics and the equator. His work was improved upon in the Renaissance by Tycho Brahe (1546 - 1601). Public figures would have an armillary sphere incorporated into their portraits to indicate their wisdom and knowledge.

I've written about clocks before, but I don't recall learning that Gerbert d'Aurillac invented it. I want to check that out; I'll let you know what I find.

The Ottonian Renaissance

Although we use the term "renaissance" to refer primarily to a rebirth of art and culture that started in 14th century Italy and spread throughout Europe, the truth is that there were several rebirths of culture between the Fall of Rome and the 14th century. I discussed this a decade ago here. One such rebirth took place during the Ottonians in Germany in the 10th century.

Part of this was not so much a rebirth as an influx of culture from the east: the Byzantine Empire maintained some of what Western Europe "lost" during those centuries. When Otto I married his son, Otto II, to Theophanu, the daughter of the Byzantine Emperor John I Tzimiskes, he opened the door to Byzantine art and increased commerce. Another important figure involved was Gerbert of Aurillac, who became Pope Sylvester II during the reign of Otto III.

Sylvester II introduced the abacus for computation, and wooden terrestrial spheres for the study of the movement of planets and constellations. He composed De rationalis et ratione uti (Of the rational and the use of reason) and dedicated it to Otto III. Promoting reason over faith was an important step in the study of the sciences. Sylvester also promoted the expansion of abbey libraries, particularly at Bobbio Abbey (where St. Columbanus wound up earlier), which had almost 600 works.

Arts and architecture also stand out in an examination of the Ottonian Renaissance. The revival of the Holy Roman Empire brought inspiration to think on a grander scale and create art and buildings that reflected the grandeur to which the Ottonians believed they were heir. Large bronze doors on churches and gilded crosses became more common. Ottonian patronage of monasteries produced grand illuminated manuscripts. One of the most famous scriptoria was Reichenau, which produced Hermann of Reichenau. This is also the period of the literary output of Hrotsvitha of Gandersheim.

A campaign of renovating churches and cathedrals also took place. (The illustration is an ivory plaque showing Otto I on the left, shown smaller than the saints, presenting Magdeburg Cathedral to Christ.) Longer naves and apses were inspired by Roman/Byzantine basilica. Many of these church designs and re-designs came form the hand of Otto I's brother, Bruno the Great. Bruno extended the cathedral in Cologne to rival the size of St. Peter's in Rome (Cologne Cathedral burned down in 1248, alas). He also built a church dedicated to St. Martin of Tours.

Ivory carving and cloisonné enamels were also widely produced in this era. A major workshop for cloisonné enamels was established by Archbishop Egbert of Trier, using a Byzantine technique of "sunken" enamel, where thin gold wire was soldered to a base, and colored glass melted into the spaces, as opposed to the original style of affixing gemstones as an inlay.

I find Ottonian art, though lovely, does not tickle my interest as much as those "wooden terrestrial spheres" of Pope Sylvester, so I'm going to look into those for next time.

The Ottonians

The Ottonians, the Ottonian dynasty, the Ottonian Period in Germany—all these refer to the same topic: a Saxon dynasty of German monarchs (three of whom were named, natürlich, "Otto") that lasted from 919 until 1024CE.

Its founder was not named Otto, however (although his father was); that was Henry the Fowler (876 - 936), son of Otto the Illustrious. He was named primus inter pares (Latin: "first among equals") by the German dukes of Bavaria, Swabia, and Lotharingia during the Hungarian invasions of East Francia, and named Rex Francorum ("King of the Franks") in 919. He was victorious over the Hungarians and amassed sufficient power to be uncontested when he passed his title onto his son, Otto I (912 - 973).

Also known as Otto the Great, one of the chief historical events connected to him is the restoration of the Holy Roman Empire (which, it should be noted, was by any standard definitions neither "holy" nor "Roman" nor an "empire"). Sure, the administrative structure needed to manage the large area (shown in the illustration) was inherited from the Carolingians and Charlemagne, and they got it from the Romans, but it was nowhere near what the Roman Empire had been.

Pope John XXII, however, wanted Otto's help in controlling Rome and the Lombards. Otto was a good choice: he was geographically close to Rome, he had defeated the pagan Magyars in 955, making him look like a hero for Christianity, and he was (in some ways) the successor of a previous Frankish king, Charlemagne, who had been made Holy Roman Emperor in Christmas Day in 800. Otto, whose wife was the Italian Adelaide of Burgundy (931 - 999). stepped in for the pope and conquered the Kingdom of Italy in 961. He was crowned Holy Roman Emperor on 2 February 962.

The "re-creation" of the empire and its expansion to much of central and Southern Europe sparked a bit of a cultural resurgence, the Ottonian Renaissance. This continued under Otto the Great's son, Otto II, partially because of his marriage to Theophanu, the niece of Byzantine emperor John I Tzimiskes. This helped create an influx of Byzantine art into Europe.

Otto II died after only 10 years, aged 28. His son, Otto III, was only 3 years old; his regents were his mother Theophanu, his grandmother Adelaide, and Henry II ("the Quarrelsome"), Duke of Bavaria. When he came of age, among other things he installed his confidants as popes: Pope Gregory V and the science-minded Gerbert of Aurillac, Pope Sylvester II.

When Otto III  died young (aged 21 years), he was succeeded by Henry II, a son of his regent Duke Henry. Henry was crowned emperor by Pope Benedict VIII in 1014. He founded numerous dioceses and intertwined secular and religious administrative power. When he died childless in 1024, the Ottonian dynasty ended. The crown went to Conrad II, a great-grandson of a daughter of Otto I, starting the Salian dynasty.

Before we can move to other topics, however, I want to look more at the results of the Ottonian Renaissance. See you tomorrow.

Two Dates for Hungary

St. Stephen I, King of Hungary

Today's date is important in the history of medieval Hungary for two separate events decades apart.

First, it is the anniversary of the founding of Hungary as a kingdom in 1000 CE.

Originally it was just a principality in the Carpathian Basin of Central Europe, established just prior to 900 CE. The Hungarians were semi-nomadic, pushing westward in their search for more territory. The westward push was halted by Holy Roman Emperor Otto I at the Battle of Lechfeld* on 10 August 955. This convinced the Hungarians to settle down where they were.

There was internal strife in Hungary, however. When the ruling probe of Hungary, Géza, died, his brother Prince Koppány claimed the right to rule.  This claim was challenged by Géza's son, Vajk, who had been baptized a Christian and taken the name István (Stephen). Stephen wanted to turn Hungary into a European Christian kingdom. Koppány wanted to adhere to the traditional tribal ways. Forces loyal to each clashed in 998 where Stephen, whose Christian connection brought him the support of Bavaria, prevailed. Koppány was cut into 4 pieces and the parts sent throughout the kingdom as a sign of how troublemakers could expect to end up.

On Christmas Day 1000, Stephen I was crowned King of Hungary with a crown sent to him by Pope Sylvester II, establishing Hungary as a kingdom and country in its own right. Stephen turned out to be a great friend to the Roman Catholic Church, which leads us to the second reason this date is important for Hungary.

In 1083, Stephen I of Hungary was canonized as St. Stephen. He established the presence of the church in Hungary very throughly, with six bishoprics and three monasteries and penalties for not following Christianity. Hungary became a safe route for pilgrims traveling from Western Europe to the Holy Land.

Sadly, no children by him and his queen, Gisela of Bavaria (also known as Gisela of Hungary), survived, and upon his death there was civil war. His reign was a time of peace and a golden age for the spread of Christianity in Central Europe. His feast day, 20 August, is also a holiday in Hungary celebrating the founding of the country.


*Curiously, this was the second Battle pif Lechfeld; in the first, fought in 910, Hungarians defeated a Frankish army, but failed to establish dominance in the region.

The Abacus

After mentioning Fibonacci's work, the Liber Abacus, it occurred to me that the place of the abacus in history deserved a little attention.

The Salamis Tablet, 300 BCE

Like the etymology for book, the word "abacus" does not start out to "mean" a frame with wires and beads. The word "abacus" first enters print in the English language in 1387. The Latin word from which it is lifted refers to a sandboard, a counting board covered in sand that allows you to draw with your finger. Latin took the word from the Greek abax, abakos, a board covered with sand for the purpose of drawing figures and calculating. At some point, the sand was replaced with counters of wood or stone that were moved from column to column for calculations, and the board itself was designed to facilitate calculations

In 1846, on the island of Salamis, a white marble counting board was discovered. The Salamis Tablet has been studied extensively, and one scholar has made a video of its proper use.

But when did abacus come to refer to the wooden frame with beads on wires? A reconstruction of a 1st century Roman abacus shows a board with grooves to keep the round beads in line. Visually, it resembles the abacus with which we are familiar. Gerbert of Aurillac (c.946-1003), one of the most influential scientific minds of his era, pushed the use of the abacus as a method of calculating much more swiftly than when using Roman numerals. He was able to promote its use even more when he became Pope Sylvester II.

The abacus in the form we think of it seems to come from China in the 2nd century BCE. Called a suanpán ("counting tray"), it was built with rods that held beads, 2 on an upper deck and 5 on a lower. Now called the "2/5 abacus," the two decks allowed the user to use larger numbers without adding 1+1+1+1, etc. Other versions had different numbers of rods, and different numbers of beads on them.

Abacus showing 87,654,321

Visually, it is very much like the Roman abacus mentioned above. Commerce between Rome and China was not unknown, but a direct influence cannot be proven. Still, the wooden-framed Chinese suanpán was so much like the Roman abacus that it was natural that the West would use the same name for the new device. In fact, no one type of the many objects used for calculating universally replaced the others. Counting boards of clay or wax were used well past the Middle Ages. In fact, until just after 2000, some accounting schools in China required proficiency in using the bead abacus.