WE HAVE COME to see just one thing. Just a few steps to the right hand side of the Church of San Pantalon is the small square (Campiello) of Ca' Angarini, named after a wealthy family from Piacenza who once lived here. What we are looking for is the big, round, stone medallion clipped to the wall.

With a sword in one hand and his imperial orb in the other is an emperor wearing a Byzantine costume, Byzantium being the Eastern side of the Roman empire with its capital in Constantinople, today's Istanbul, dating from 330 AD.

So which emperor is he? Some scholars reckon it is probably Isaac II Angelus, who ruled from 1185-1195, and who was overthrown, imprisoned and blinded by his brother who declared himself emperor Alexius III, although there is an argument that it is Alexius on the medallion, despite him proving a weak, greedy and unpopular ruler.

Whether it is true or not the best story concerns Lorenzo Tiepolo, a Venetian general who was sent to fight the Genoese in what is modern day Israel but was then Jerusalem. The Genoese and the Venetians both laid claim to the ownership of the monastery of St Sabbas in the fortified city of Acre.

The monastery lay on the boundary of the Venetian and Genoese quarters within the city. Both were there to take advantage of trade routes around the Mediterranean. In 1256, supported by allies from Pisa, the Genoese seized the monastery, attacked and evicted the Venetians. Skirmishes continued until Lorenzo Tiepolo was sent from Venice with a fleet to break the Genoese blockade and take back possession of their quarter.

In certain parts of Venice Tiepolo was not highly thought of and legend has it that he was asked to bring back a memento in the unlikely event that he was successful. Suffice to say Tiepolo defeated the Genoese fleet and destroyed their fortifications in June 1258 and took back the medallion to Venice.

Before being moved to its present position the medallion was originally thought to have been placed on the ground between Ca' Angaran, home to one who had doubted Tiepolo, and the church of Saint Pantaleon, so that every time he went to mass he would have to walk over the trophy denoting Tiepolo's bravery and daring.