Santa Teresa alle Quattro Fontane was the 17th century church, now demolished, of a Carmelite convent on the south side of what is now Via XX Settembre, east of Quattro Fontane where the Defence Ministry now is. This is in the rione Castro Pretorio.
The dedication was to St Teresa of Avila.
The sisters were Discalced Carmelite nuns, Teresiane, and so the complex was dedicated to the saint who was the founder of the congregation. The convent itself was founded in the 17th century by Caterina Cesi, widow of the Marchese della Rovere and the architect was Bartolomeo Breccioli.
The convent was sequestered at very short notice by the Italian government in 1876, which seized and sold off all religious items in the church and sacristy before demolishing the complex for the Defence Ministry. One of the baroque altars ended up in the new English church of San Giorgio e dei Martiri Inglesi, in Via Sebastianello.
There also used to be a convent of the "other" Carmelite nuns, the ones that did not accept the Discalced reform, further east along the street at Incarnazione del Verbo Divino. It suffered the same fate.
The church was exactly halfway between the junctions of the present Via XX Settembre with the Via delle Quattro Fontane and the Salita di San Nicola da Tolentino.
There is nothing to mark the site of the church on its side of the street, where the overbearing Defence Ministry building dominates, but it was opposite where there is now a monumental neo-Baroque entrance with a rusticated arch framed by a pair of columns in another building. The row of bollards and chains marks the line of the façade.
The convent was fairly large. It was arranged around three arcaded sides of a cloister, with a western wing, a northern wing along the street with the main entrance and an eastern wing containing the church. The southern side of the cloister opened straight into the sister's large garden. The cloister garth was also laid out with formal flowerbeds, and must have been an attractive spot.
The left hand wall of the church was also part of the partition wall between this convent and that of the Incarnazione next door. Interestingly, there was also a doorway between the two convents at the north-eastern corner of the Teresian sisters' garden; one wonders why.
The church was quite large, on a rectangular plan. The ceiling vault was supported on two pairs of pilasters, and there was a separate square apse with a triumphal arch.
Chandlery, P: Pilgrim-Walks in Rome, Manresa Press 1903