Of ancient foundation, Santi Quaranta Martiri e San Pasquale Baylon, to give the church its full name, is an 18th century convent church. The church was rebuilt in 1747 to a design by the architect Giuseppe Sardi.
The church is jointly dedicated to the Forty Martyrs of Sebaste and to St Paschal Baylon. It is also known as the Chiesa delle Zitelle (Church of the Spinsters). Paschal Baylón (1540-1592) was a Spanish Franciscan. He was canonised by Pope Alexander VIII (r. 1689-91) on October 16th 1690. His feast day is May 17th.
The inscription on the facade reads: DEO IN HON · S·S · XL · MARTYRU AC S·PASCHALIS BAYLON DIC · ANNO DNI MDCCXLV.