Sant'Ambrogio della Massima
is a 17th century monastic church in in the rione Sant'Angelo.. The dedication to St Ambrose, the 4th century Archbishop of Milan and Doctor of the Church.
For reference, a plan of the church is available here
According to tradition, the monastery and church had their origins in a house occupied by St Marcellina, the older sister of St Ambrose, which was transformed by her into a convent in 353. The first documentary reference is in the Liber Pontificalis of 803, which mentions a donation to the Monasterium Sanctae Mariae, nomine Ambrosii or "The monastery of St Mary, called 'of Ambrose'".
The present church, in which remains of the older church are incorporated, was built between 1606 and 1634 by Orazio Torriani
, to the design of Carlo Maderno
. The façade collapsed in 1862 and was rebuilt to a design by Giacomo Monaldi
. In 1863 he oversaw a major re-ordering of the church, changing the nuns' choir into a sacristy and providing a gallery over the present entrance. The monastery was built to a design by Giovanni Battista Mola
Since 1861 the monastery has been the headquarters of the Subiaco Cassinese Congregation of Benedictines