Of ancient foundation, the titular church of Sant' Eustachio in Campo Marziowas rebuilt between 1650 and 1734. The facade is crowned with a stag's head, a reference to the conversion of St Eustace, to whom the church is dedicated. The grand campanile (late 12th century) was left untouched.
Interior
The interior comprises a single nave flanked by chapels. The sanctuary is divided from the nave by a low balustrade which sports the coat of arms of Cardinal Neri Maria Corsini.
High Altar
The altarpiece is by Francesco Fernandi (1679-1740) and depicts The Martyrdom of St Eustace.
Chapel of the Immaculate Heart of Mary
The second chapel on the left is dedicated to the Immaculate Heart of Mary. It was fitted out by Melchiorre Passalacqua in 1771, with stuccoes by Agostino Penna. The fine Baroque altar has two altarpieces; the upper one is an icon of the Immaculate Heart of Mary, which is set in a Baroque Glory. The lower altarpiece depicts St Francis of Paola (1416-1507), to whom the chapel was originally dedicated. The altarpiece is crowned by the monogram of Mary, which is flanked by two angels.
Funerary Monument of Silvio de Cavalieri
There is a fine funerary monument (1715) to Silvio de Cavalieri in the first chapel on the left.