Tradition has it that this church was founded by St Magnus in the eighth century, but the present free-standing building - one of only two churches in the city that you can walk around - dates from the 17th century. The ceiling has a lively fresco by Gaspare Diziani of St Michael Driving out Lucifer, with Lucifer apparently tumbling out of the heavy stucco frame into the church. There are matching Last Suppers on either side of the organ (by Bonifacio de' Pitati on the left, and a follower of Titian on the right).
But the real jewels of the church are on the organ loft, where five compartments, painted by Giovanni Antonio Guardi (or perhaps his brother Francesco), recount the story of Tobias and the Angel (1750-53). They are works of dazzling luminosity, quite unlike anything else done in Venice at the time. The paintings and the story they recount play a significant role in Sally Vickers' novel Miss Garnet's Angel (2000).