REBECCAC84: One of those strange glyphs Shaun mentioned is on this landmark. You should go find it!
The Scuola Grande di San Marco was one of the six large charitable organizations founded in Venice to help citizens afford food, dowries, processions, marriages, burials and anything else they might need. Notably, membership was open to any citizen of Venice, not just the elite.
Citizenship status was conferred on third generation Venetians or those who had paid taxes for fifteen years, meaning that Venetians were pretty xenophobic, except when you gave them money.
The façade of the building, which was built in 1260, was destroyed in a 1485 fire, causing it to be rebuilt in its current, opulent Byzantine form.