Santa Maria in Montesanto

Map of the Churches of Rome
Church of Santa Maria in Montesanto, Rome
Santa Maria in Montesanto
In 1662, Pope Alexander VII (r. 1655-67) ordered a pair of churches to be erected on the south side of Piazza del Popolo to provide a grand backdrop to the square from the viewpoint of anyone entering through the Porta del Popolo.

The church on the left is Santa Maria in Montesanto, the one on the right is Santa Maria dei Miracoli. They are often referred to as the 'twin' churches.
The 'Twin' churches, Piazza del Popolo, Rome
The 'Twin' Churches
Cardinal Girolamo Gastaldi put up a large sum of money in exchange for being commemorated in the decoration of the two churches. The first architect was Carlo Rainaldi, who planned two identical circular buildings. Unfortunately, Pope Alexander died in 1667 and his successors had little interest in the project. Work stopped for four years but resumed in 1671 under Carlo Fontana, who finished it in 1673 in time for the Jubilee of 1675. (Santa Maria dei Miracoli was completed three years later.) The change of the ground plan from circular to elliptical may have been suggested by Bernini. 

At first glance the two churches seem to be identical in design, but this is not the case. For instance, the dome of Santa Maria in Montesanto is dodecagonal not octagonal. The lanterns are also subtly different, as are the bell towers. 

The facade is dominated by the portico, which bears a dedication to Cardinal Gastaldi. The ten statues on the roofline depict Carmelite saints (the church originally belonged to the Carmelite Order). 
Interior of church of Santa Maria in Montesanto, Rome
Interior
The entrance of the church is on the main axis of the ellipse. To each side are three chapels. The six chapels are separated by gigantic Corinthian pilasters supporting an entablature, which runs around the entire church. ​
Dome Interior, Church of Santa Maria in Montesanto, Rome
Dome Interior
On this the dome sits; there is no proper drum. The four statues are by Filippo Carcani, also known as Il Filippone, who did much of the rest of the stucco decoration.
High Altar, Santa Maria in Montesanto, Rome
High Altar
Over the entrance to the sanctuary is the coat-of-arms of Cardinal Gastaldi, flanked by a pair of stucco angels. The high altar was designed by Mattia De Rossi; the painter of the altarpiece is unknown. The bronze busts to either side of the altar depict Pope Alexander VII (r. 1655-67), Pope Clement IX (1667-69), Pope Clement X (r. 1670-76) and Pope Innocent XI (1676-89). They are the work of the Roman sculptor Girolamo Lucenti (1627-98). ​
Chapel of Santa Maria Maddalena de' Pazzi, Santa Maria in Montesanto, Rome
Cappella di Santa Maria Maddalena de' Pazzi
The vaults of two of the side chapels warrant particular attention. The second chapel on the left is dedicated to St Mary Magdalene de' Pazzi (1566-1607), a Carmelite nun and mystic from Florence. The stucco work in the sumptuously ornate vault is by Filippo Carcani. 
Vault, Chapel of the Crucifixion, Santa Maria in Montesanto, Rome
Cappella del Crocifisso
The first chapel on the right is dedicated to the Crucifixion. The rich stucco work in the vault is by Pietro Papaleo (c. 1642-1714). ​

Santa Maria in Montesanto is known locally as the ‘Chiesa degli Artisti’ ('Church of the Artists'). It earned this sobriquet as a result of its proximity to the artists' quarter, which, following the building of the Spanish Steps, grew up in the surrounding area. Artists would use the Spanish Steps to exhibit their works. Models would also congregate at the bottom of the steps, in the hope of getting work. In the absence of a neighbourhood church, Santa Maria in Montesanto performed this function for the artistic community. 

Lovers of Baroque music may like to know that, in July 1707, three works by a young Georg Frederick Handel (1685-1758) were premiered in Santa Maria in Montesanto: Nisi Dominus, Dixit Dominus and Salve Regina.