Venitians have always been well known for their love for gambling, but it was not legalized in the old times.
Only possibility of Gambling - for a few centuries - was in St. Mark's Square, between the two columns.
But Venitians would find any way of satisfying their addiction - after all economy was running well in the city - money was moving around, and ... they simply loved to play.
It was also a big trend in all Europe, starting from the XIV century, more or less. And Venice was probably one of the first to dip heavily into gambling.
There are documents stating that the first card game factory in Venice started its business in 1391.
There had been a very singular law regarding gambling, made in March 18, 1266, stating that "if a guy got caught gambling who couldn't pay the 10 soldi fine, he could be thrown in the water".
Fast, real-time justice.