Originally this island near the Giudecca and San Giorgio in Alga was called Sant’Angelo di Concordia (or Sant'Angelo di Contorta, in dialect) and by the 11th century, like many of the small islands in the lagoon, it had its first monastery.
Eventually this was taken over by Benedictine nuns, who, as was frequently the case in Venice, had been compelled to take vows. Isolated, they rebelled and merrily turned Sant' Angelo into brothel. So many fishermen returning home to the Lido from the Rialto market took to stopping off and spending their earnings that their wives reported the nuns to the authorities, and in 1474, they were moved to a convent on the Giudecca where the authorities could keep an eye on them.
The nuns were replaced by monks, but 80 years later they left when the lagoon started silting up and smelling bad. The monks were replaced by a tiny fort, with a stockpile of 800 barrels of gunpowder, and the island henceforth became known as Sant’Angelo della Polvere ('of the Gunpowder'). In 29 August 1689, it was struck by lightning and blown to smithereens.
This did not deter the Austrians, who rebuilt a fort here in the 19th century, although they made sure to enclose the powder magazines in lightning-resistant armour. These have collapsed since and today Sant'Angelo is populated by rabbits and ducks... but as with many other small, neglected islands, there have been debates about its future.
Image by Leonardo, Creative Commons License