The mechanical clock: origin and purpose

Although many other late-medieval nova reperta – including the paper, printing, gunpowder, and the compass – originated in Asia, the mechanical clock was invented in and developed almost entirely in Europe. In origin, this invention was profoundly rooted in the culture of the European Middle Ages and driven by cultural and environmental climate factors. 

Central to many of the monastic orders of medieval Catholicism was a daily cycle of prayer – known as the officium divinum (‘divine duty’) and opus Dei (‘work of God’) – which was outlined in a ‘book of hours’.  Most monastic rules prescribed prayers at seven fixed times, which included not only the end of the day, just before retiring (known as ‘Compline’, about 7:00 p.m.) and at dawn (‘Lauds’, about 5:00 a.m. depending on the season), but also a midnight prayer known as ‘Vigil’ or ‘Matins’ (at about 2:00 or 3:00 a.m.). Synchronization of this cycle required timepieces which could function day and night and in all weathers. The freezing condition of northern European winters limited the utility of water clocks for this purpose. 

The most important purpose of the earliest clocks was therefore to waken the sleeping monks for Vespers. For this reason, these clocks signalled the time not by moving a dial but by sounding a bell. Accordingly, the English word ‘clock’ derives from the post-classical Latin word cloca or clocca which is the root of the word for ‘bell’ in French (cloche), Dutch (klok), and German (Glocken).

Interestingly, this image from a manuscript of the popular Horologium Sapientae (1328-30) by the German Dominican Heinrich Suso (1295–1366) shows the two main ways of indicating the time: visually, by means of the 24-hour dial on the left, and audibly, via the carillon on the right (a set of bells which could play a variety of tunes depending on the hour). 

Commentary: Howard Hotson (May 2024)