Like most of his fellow Olympians, Apollo did not hesitate to intervene in human affairs. It was he who brought about the demise of the mighty Achilles. Of all the heroes besieging the city of Troy in the Trojan War, Achilles was the best fighter by far. He had easily defeated the Trojan captain Hector in single combat. But Apollo helped Hector's brother Paris slay Achilles with an arrow.
When someone died suddenly, he was said to have been struck down by one of Apollo's arrows. Homer's epic of the Trojan War begins with the god causing a plague by raining arrows down upon the Greek camp.
As god of music, Apollo is often depicted playing the lyre. He did not invent this instrument, however, but was given it by Hermes in compensation for cattle theft. Some say that Apollo did invent the lute, although he was best known for his skill on the lyre.
He won several musical contests by playing this instrument. In one case he bested Pan, who competed on his own invention, the shepherd's pipe. On this occasion, King Midas had the bad sense to say that he preferred Pan's music, which caused Apollo to turn his ears into those of an ass.