Above the main Cathedral door is a 24 hour clock with fresco portraits of four
evangelists by Paolo Uccello (1443). This unusual clock only has an hour hand
(minute hands came into regular use around 1690), and runs in a direction we
consider to be “counter” clockwise. The position of 1 is at the bottom, and the
numbers for 4, 9, 14, 19 and 24 are not what we consider correct for Roman Numerals.
This clock is still in working order, and shows the 24 hours of the hora italica
(Italian time) - a period of time ending with sunset at 24 hours.
This time format was used until the 18th Century.
see also History Section
Spot The Clock
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