is a 18th century titular, collegiate and former parochial church dedicated to the Roman martyr St Eustace. The church is located in rioni St Eustachio, a block west of the Pantheon and via della Rotonda, and a block east of Sant'Ivo alla Sapienza.
For reference, a plan of the church is available here
An ancient pre-8th century church on this site was seriously damaged by Tiber flooding. A campaign of rebuilding was begun in 1650, under the architect Cesare Crovara
. In 1706 Giovan Battista Contini
took over and designed the side chapels and portico. After a pause in the work, from 1724 to 1727 the apse and transept was constructed firstly by Antonio Canevari
, and then by Nicola Salvi
. In 1736 Giovanni Domenico Navone
was appointed chief architect and he applied finishing touches in the following year. Around 1724, artist Giacomo Zoboli
was hired to paint the transepts. In 1734, the new church was consecrated.
The deaconry was established around the year 600. Among its titulars were the popes Gregory IX, Alexander IV, Antipope John XXIII, Pius III and Paul III.
In 1861 there was a restoration of the interior. From 1930 to 1940 there was a long campaign of restoration, the most notable result of which was the decoration of the Chapel of the Sacred Heart by Corrado Mezzana
. The same artist also executed the woodwork of the confessionals in the transept.