Apollo (Roman)

Apollo can change into his Roman aspect of Apollo (sometimes called Phoebus). In this form, he becomes more disciplined, militaristic, and warlike. Apollo may have children along with his descendants at Camp Jupiter near San Francisco. The Roman worship of Apollo was adopted from the Greeks. To the Romans, Apollo was known commonly as Phoebus in his capacity as the god of the sun. During the Second Punic War, the Ludi Apollinares (Apollonian Games) were instituted in his honor. 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.

History
Apollo was son of Jupiter and Latona, and brother of Diana, and of all the divinities in the pagan world, the chief cherish-er and protector of the polite arts, and the most conspicuous character in heathen theology; nor unjustly, from the glorious attributes ascribed to him, for he was the god of light, medicine, eloquence, music, poetry and prophecy.

Amongst the most remarkable adventures of this god, was his quarrel with Jupiter, on account of the death of his son Aesculapius, killed by that deity on the complaint of Pluto, that he decreased the number of the dead by his cures. Apollo, to revenge this injury, killed the Cyclops who forged the thunder-bolts. For this he was banished heaven, and endured great sufferings on earth, being forced to hire himself as a shepherd to Admetus, king of Thessaly. During his pastoral servitude, he is said to have invented the lyre to sooth his troubles. He was so skilled in the bow, that his arrows were always fatal. Python and the Cyclops experienced their force.

His temple at Delphi became so frequented, that it was called the oracle of the earth; all nations and princes viewing in their munificence to it. The Romans erected to him many temples.

The Son of Neptune
While not seen in the series so far, Octavian is a legacy of Apollo and has the gift of prophecy, even if his messages don't always appear clearly.

Frank Zhang also mentions Apollo several times, wishing to be claimed by him as he is skilled in archery. Frank also mentioned to Percy that while Camp Jupiter normally doesn't approve of archery, children of Apollo are allowed to train in this field. Frank later realized that if he was claimed by Apollo, he would be related to Octavian.

Trivia

 * Octavian, the Augur at Camp Jupiter, is a legacy of Apollo and supposedly has the gift of prophecy. Curiously, Octavian's namesake Augustus was sometimes said to be a son of Apollo.
 * Apollo is more commonly known as the God of the Sun in his Roman counterpart.