Temple of Apollo Sosianus ruins, three re-erected columns, the Capitoline hill in background.

The Temple of Apollo Sosianus (previously known as the Apollinar and the temple of Apollo Medicus) is a Roman temple dedicated to Apollo in the Campus Martius, next to the Theatre of Marcellus and the Porticus Octaviae, in Rome, Italy. Its present name derives from that of its final rebuilder, Gaius Sosius. The three re-erected columns of the temple which survive to full-height today belong to the Augustan rebuild, but the cult of Apollo had existed in this area since at least to the mid-5th century BC. when an Apollinar (a sacred grove or altar) was recorded on this site. The temple's ruins were occupied in the post-Roman period by medieval dwellings right up to the 1930s, when these were demolished between 1926 and 1932 to allow the theatre of Marcellus to be seen in isolation. In those same works the remains of the fallen colonnade were recovered in the very positions in which they had fallen, inside the arches of the theatre and as a result in 1937 and 1938 the podium's remains were excavated. In 1940 the fallen columns were raised on this podium, though probably not in their original positions.

The Capitoline Hill (Latin: Collis Capitōlīnus; Italian: Campidoglio), between the Forum and the Campus Martius, is one of the seven hills of Rome. It was the citadel (equivalent of the ancient Greek acropolis) of the earliest Romans. The name capitol seems to have meant "dominant height".

more on https://en.wikipedia.org/wiki/Temple_of_Apollo_Sosianus and https://en.wikipedia.org/wiki/Capitoline_Hill