The Roman empire developed a craze for antique statues, paintings and other objects from Greece, which were plundered and brought to the capital for sale to Roman collectors.
These crosses stand for the names of ships or towns that they sank or plundered.
Here we are reminded again of the song about "The King of England's Son," for in it mention is made of the custom prevalent at the time, when knights and squires plundered those who had been saved from shipwreck.
There it stands, unsheltered, plundered, and broken.