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This generous adventurer, prompted by an insatiable thirst for information, is said to have secretly withdrawn himself from his monastery of Fleury in Burgundy, and to have spent several years among the Saracens of Cordova.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.

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.