Carceri di Sant'Ansano, Siena

Adjacent to the tower is the former Istituto Santa Teresa.43°18′52″N 11°19′42″E / 43.31448°N 11.328202°E / 43.31448; 11.328202 The church or oratory was built in 1444 and consecrated in 1448.

The brick exterior remains asymmetric and unfinished with some round windows walled up.

Over the entrance portal is a retouched fresco depicting the Madonna and Child with Saints Ansano and Caterina da Siena by Francesco Rustici.

However a problem with the story is that the tower likely dates from the 13th century, hence was unlikely to have existed as such during the 4th-century rule of Diocletian during which Sant'Ansano was martyrdom.

He was taken outside of the city to be boiled in oil, near the town now called Sant'Ansano, but remained unscathed.