Time Off the Wrist: the Zytglogge of Bern

While mankind’s preoccupation with timekeeping is nearly as old as civilization itself, mechanical clockmaking didn’t really come into its own until the late Middle Ages/early-Renaissance. The advent of the first mechanical escapement, the verge escapement, in the mid-1300s allowed timepieces to be separated from a source of running water for continuous power. For the first time, a mechanical clock could be placed anywhere (at least anywhere that could fit a clock tower) and used to bring timekeeping to the public.

At the dawn of the 15th century, much of Europe was divided into small, fiercely competitive city-states. Trade across the continent and beyond was burgeoning, and wealthy regions used this influx of new income to outdo each other however they could. Some, like Florence or Venice, invested huge sums in architecture and the arts, building stunning cathedrals and palaces. Others across Europe, however, put their newfound wealth into the new field of mechanical horology, creating clocks as city centers that stand to this day. In the second installment of Time Off the Wrist, we’re taking a look at one of the greatest examples of these—the Zytglogge in Bern, Switzerland.

Once forming part of the western wall of the city, the Zytglogge (“Time Bell” in Swiss-German) of Bern has remained a fixture in the community for eight centuries, even as the urban sprawl enveloped it. First constructed in 1218, the original tower served as a gate and guard post against potential German and Italian invaders for over a century.

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The name of the original builder of this mammoth movement is lost to history; the nearest city records only indicate that the tower was expanded with a new lantern and decorative turrets around the mid-1480s.

However, the next chapter of the Zytglogge’s story is very well documented. The clock tower’s movement broke down in 1527, grinding the iconic symbol of the city to a halt. The man elected to repair the Zytglogge, a local blacksmith by the name of Kaspar Brunner, had no previous experience in horology. Nevertheless, his promise to improve on the original design and his low bid of 1,000 Bernese gulden netted him the job. Over the next three years, Brunner lived up to his promise. The astronomical clock’s movement was completely redesigned, adding several more features and reinforcing parts throughout. The new Brunner movement was so robust that it continues to power the Zytglogge to this day, after 487 years of continuous running without any major breakdowns.

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Despite changes to the outer facade over the centuries, the beating heart of the Zytglogge has remained unchanged since 1530 while sporting a dizzying array of complications. The astronomical dial alone features six: hours, moon phase, weekday, a day/night indicator (also indicating dawn and dusk times throughout the year), Julian calendar, and a classical zodiac indicator.

The famed astronomical clock dial is fashioned after an astrolabe. The clock is backed by a planisphere projected onto a plane depicting three distinct zones: the night sky (in black), dawn (deep blue), and day (light blue). Around the planispehere is a moving metal cutout with the signs of the zodiac, and around that are orbiting sun and moon indicators. This cutout also features the Julian calendar. It does not track leap years, so it has to be manually adjusted each leap year. The 24-hour Roman numeral index trimming the clock is the main time indicator. The clock is a wonderful piece of engineering and art, and because the whole thing is displayed in an ornate combination of red and gold leaf, the tower is brilliantly visible across town.

As impressive as the Zytglogge is, however, 500 miles to the northwest lies an even more fascinating piece. In a future installment of Time Off the Wrist, we’ll take a look at the Prague Orloj in the heart of the Czech Republic.