This is the spot where, in the 5C BC, the first temple dedicated to the Greek god Apollo stood. He was initially revered by the Romans for his power to stave off illnesses (Apollo Medicus). In 34 BC, Caius Sosius, governor of Cilicia and Syria, had the sanctuary rebuilt in marble and it was named Temple of Apollo Sosianus in his honour. The three elegant grooved columns with Corinthian capitals, set upright in 1940, belonged to this building's pronaos.