The imposing Baroque church of Val-de-Grâce is part of a well preserved 17th C convent, now a military hospital. Anne of Austria, Louis XIII's wife, had purchased the conventual buildings and presented them to a house of Benedictine nuns, vowing at the same time to give them a church if she gave birth to an heir to the throne. In 1638 she had a son, the future Louis XIV, and in 1645 she fulfilled her vow, commissioning Jacques Lemercier to build the church, which was completed by Gabriel Le Duc in 1667. It was the only Baroque church in Paris so strongly influenced by Rome, the great center of 17th C Baroque architecture.
Lemercier modeled the west front on the church of Santa Susanna in Rome with its double row of columns, but in a more vigorous and upward striving form. The dome, modeled on St Peter's in Rome, is of livelier effect with its sculptured vases, windows and a relief frieze of the royal fleurs de lys and the initials A and L; while the drum is given a strongly plastic form, with projecting pilasters, overhanging cornices and deeply set windows.
The interior of the church is also marked by the plastic approach which governs its architecture and decoration as a whole. The barrel-vaulted nave consists of three bays, in each of which are side chapels. On the round- headed arches are reliefs of the Virtues, and in the medallions are the Forefathers of Christ. The crossing is given greater emphasis by a stepped dais bearing a baldachin supported on columns - again modeled on Bernini's baldachin in St Peter's. In the dome (height 40m/130ft, diameter 17m/55ft) is a huge fresco (by Pierre Mignard, 1665) of God the Father surrounded by saints and martyrs. The chapel on the left of the choir has a fresco portrait of Anne of Austria in the dome; the chapel on the right, formerly the nuns' choir, is dedicated to St Louis (Louis IX).