Sant'Agnese in Agone

Sant'Agnese in Agone (also called Sant'Agnese in Piazza Navona) is a 17th-century Baroque church in Rome, Italy. It faces onto the Piazza Navona, one of the main urban spaces in the historic centre of the city and the site where the Early Christian Saint Agnes was martyred in the ancient Stadium of Domitian. Construction began in 1652 under the architects Girolamo Rainaldi and his son Carlo Rainaldi. After numerous quarrels, the other main architect involved was Francesco Borromini.

The church is a titular deaconry, with Gerhard Ludwig Müller being the current Cardinal-Deacon.

The building of the church was begun in 1652 at the instigation of Pope Innocent X whose family palace, the Palazzo Pamphili, is adjacent to this church. The church was to be effectively a family chapel annexed to their residence (for example, an opening was formed in the drum of the dome so the family could participate in the religious services from their palace).

The first designs for a centralised Greek Cross church were prepared by the Pamphili family architect, Girolamo Rainaldi, and his son Carlo Rainaldi in 1652. They reorientated the main entrance to the church from the Via Santa Maria dell’Anima, a street set one urban block away from the piazza, to the Piazza Navona, a large urban space that Innocent was transforming into a showcase associated with his family. It had been the intention to build the new church over the old church which would become the crypt; this meant the new church was to be raised well above piazza level, but this idea was abandoned once construction started. The original drawings are lost but it is thought that the Piazza Navona facade design included a narthex between two towers and broad stairs descending to the piazza.

...
Wikipedia