On the occasion of a pestilence in the 430s BCE, Apollo's first temple at Rome was established in the Flaminian fields, replacing an older cult site there known as the "Apollinare". During the Second Punic War in 212 BCE, the Ludi Apollinares ("Apollonian Games") were instituted in his honor, on the instructions of a prophecy attributed to one Marcius. In the time of Augustus, who considered himself under the special protection of Apollo and was even said to be his son, his worship developed and he became one of the chief gods of Rome.
When was the Second Punic war?
212 BCE