Subject info:
Apollo the Citharist. Apollo Ephebos. The god Apollo manifesting as a youth. In his right hand he holds a plectrum for strumming the cithara he held in his other hand, now lost.

First century bce. Copy of a Greek original from ca. 470 bce. Found at Pompeii, House of the Citharist.

Apollo:
The son of Zeus and Leto, and the twin brother of Artemis. Apollo was the god of music (principally the lyre, and he directed the choir of the Muses) and also of prophecy, colonization, medicine, archery (but not for war or hunting), poetry, dance, intellectual inquiry and the carer of herds and flocks. He was also a god of light, known as "Phoebus" (radiant or beaming, and he was sometimes identified with Helios the sun god). He was also the god of plague and was worshiped as Smintheus (from sminthos, rat) and as Parnopius (from parnops, grasshopper) and was known as the destroyer of rats and locust, and according to Homer's Iliad, Apollo shot arrows of plague into the Greek camp. Apollo being the god of religious healing would give those guilty of murder and other immoral deeds a ritual purification. Sacred to Apollo are the swan (one legend says that Apollo flew on the back of a swan to the land of the Hyperboreans, he would spend the winter months among them), the wolf and the dolphin. His attributes are the bow and arrows, on his head a laurel crown, and the cithara (or lyre) and plectrum. But his most famous attribute is the tripod, the symbol of his prophetic powers.

When the goddesss Hera, the wife of Zeus (it was he who had coupled with Leto) found out about Leto's pregnancy, she was outraged with jealousy. Seeking revenge Hera forced Leto to roam the earth in search of a place to give birth. Sicne Hera had forbidden Leto to stay anywhere on earth, either on terra-ferma or an island at sea, the only place to seek shelter was Delos, being in the center of the Aegean, and also difficult to reach, as there were strong under-currents, because it was said to be a floating island. Because it was a floating island, it was not considered either of Hera's prohibitions, and so Leto was able to give birth to the divine twins Apollo and Artemis (before Leto gave birth to Apollo, the island was encircled by a flock of swans, this is why the swan was sacred to him). As a gesture of thanks Delos was secured to the sea-bed by four columns to give it stability, and from then on it became one of the most important sanctuaries to Apollo. (A variation of Apollo's birth was that the jealous Hera had incarcerated Ilithyia, the goddess of childbirth, but the other gods intervened forcing Hera to release Ilithyia, which allowed Leto to give birth ).

https://www.pantheon.org/articles/a/apollo.html

More information on other sculpture.