St Mark’s Clocktower

Twice a year, at Epiphany (6 January) and on Ascension Day (the Thursday 40 days after Easter, counting both days), the three Magi, led by an angel with a trumpet, emerge from one of the doorways normally taken up by these numbers and pass in procession round the gallery, bowing to the Virgin and child, before disappearing through the other door.

Below this is the great clock face in blue and gold inside a fixed circle of marble engraved with the 24 hours of the day in Roman numerals. A golden pointer with an image of the sun moves round this circle and indicates the hour of the day. Within the marble circle beneath the sun pointer are the signs of the zodiac in gold (these are original and date from the 1490s), which revolve slightly more slowly than the pointer to show the position of the sun in the zodiac. In the middle of the clockface is the earth (in the centre) and the moon, which revolves to show its phases, surrounded by stars which are fixed in position. The background is of blue enamel. The smaller blue circles in the four corners are not now used.