One of the most famous treasures of the Basilica San Marco in Venice is the set of four bronze horses that stand over the main doorway of the cathedral. (as always, click on the photo for a larger view) Well, actually, the ones on the outside on the roof are replicas and the originals are inside in the museum.
These magnificent beasts were taken when the Venetians sacked and looted Constantinople in 1204 during the 4th Crusade (I'll write about that fiasco in the next article). Dating from the 4th century, they are believed to be the only existing monumental Roman quadriga, that is four horses in chariot harness. They once adorned a triumphal arch in Rome. No one is certain how they made they way to Constantinople, but I imagine they were a gift to the Emperor in Byzantium.
Bringing them to Venice and placing them atop the cathedral was a symbolic act. It marked the end of Venice's status as a vassal state of the Holy Roman Empire and celebrated its birth as an independent republic. The horses soon became a symbol of of the might and power of the Venetian state, and beloved by its people.
Many of her enemies threatened to topple the horses, but only Napoleon ever succeeded. When he conquered northern Italy and ended the Venetian republic in 1797, he sent the four horses, along with many other treasures, back to Paris. There they remained until 1815 when they were returned to their old site, amid much rejoicing by the people of Venice. 
Since 1982 the original horses have been exhibited inside the San Marco Museum in order to protect them from damage from pollution. You can visit them in the museum, where you'll see tapestries, carvings, and other artifacts from the cathedral for a small fee.
But, I most enjoy climbing out on the roof, which is open to the public, and standing next to these magnificent beasts while enjoying a great view of the busy piazza below.
