2019-09 - Blog Posts

Freiburg's Schwabentor

The Germany city of Freiburg im Breisgau, on the transition between the Rhine valley plains and the hills of the Black Forest, was part of the Duchy of Swabia until it dissolved in the 13th century due to the ducal line going extinct. It was around this time that its "Swabian Gate" was built at the Eastern edge of the town, facing the Swabian heartland.

Like Schaffhausen's Schwabentor, it has undergone upgrades and downgrades, taken damage and been restored over time. The current illustrations on the tower include St George slaying the dragon (1903) on the outside, and a merchant with a cart (first painted in 1572) on the inside, just visible in the picture below.

Freiburg's Altstadt has many gorgeous, colourful houses decorated with trompe-l'oeil facades. An effort has also been made to preserve the little rivers in the streets, known as Bächle. Local superstition says that anyone who accidentally steps in a Bächle will marry a local - unusual to see a place that values clumsiness!

The best timepiece in the world (IMO): Strasbourg Cathedral's Astronomical Clock

I could go on about this thing for ages. There's so much history, so many symbols to spot, and so much information on display... This is going to be a long one.

I guess I'll start with the artistic aspect on which I have the least to say because it's the least up my alley. There's loads of mythology and Christian symbolism going on on this 18-metre tall monument, and these are the main draw for the general public, because they move around.

Like cuckoo clocks in neighbouring Schwarzwald, this astronomical clock has automatons. Every quarter hour, the lower level of the photo above sees a change of "age": a child, a young man, an adult and an old man take turns to be in the presence of Death, whose bells toll on the hour. At high noon, the upper level also moves, with the 12 disciples passing before Christ, and the rooster at the very top crows.

Moving on to what really makes me tick: the amount of information on this clock is incredible. The time, obviously, but actually two times are on display on the clock at the bottom of the picture above: solar time and official time. Given Strasbourg's position in the time zone, there is a 30-minute discrepancy between the two. Then there's all the astronomical stuff, like the phase of the Moon (just visible at the top), the position of the planets relative to the Sun (middle of the picture), a celestial globe at the base (pictures below, on the right)...

The main feature behind the celestial globe is another clock displaying solar time, with the position of the Sun and Moon (with phases) relative to the Earth, sunrise and sunset times, surrounded by a yearly calendar dial. These have remarkable features, such as the Moon hand that extends and retracts, making eclipses noticeable, and the calendar has a small dial that automatically turns to place the date of Easter at the start of each year. This sounds easy, but look up the definition of Easter and note that this clock is mechanical, no electronic calculating power involved! Either side of the base, the "Ecclesiastic Computer" and the "Solar and Lunar Equations" modules work the gears behind these features.

The accuracy of this clock and its ambition for durability are truly remarkable. Relative to modern atomic time, it would only need adjusting by 1 second every 160 years, and it correctly manages leap years (which is not as simple as "every 4 years"). It just needs winding up once a week.

Finally, the history. The monumental clock was built in the 16th century, and used the calendar dial above, now an exhibit in Strasbourg's city history museum. It slowly degraded until the mid-19th century, when Jean-Baptiste Schwilgué restored the base and upgraded the mechanisms. The "dartboard" on the old dial contained information like the date of Easter, whether it is a leap year, which day of the week the 1st January is... - all of which had to be calculated by hand before the dial was installed! - and was replaced by the Ecclesiastic Computer, which freed up the centre space for the big 24-hour clock, complete with Solar and Lunar Equations.

As you may have gathered, I am a massive fan of this clock. Of course, nowadays, all the imagery and information would easily fit into a smart watch, but a smart watch isn't 18 metres tall and powered by gravity and gears!