Long long ago the world was silent. People only spoke when they had something important to say. The silence of the people bored the gods so they wanted to find a way to fix this.
They found Apollo and asked if he could find a way to end the silence. Apollo took the woods from the trees, the hide of animals and the hair of a horse's tail to build instruments.
He shaped and hollowed out the trunk of a tree and added the horse's hair to build a guitar. He hollowed another tree then covered the opening with leather to create a drum. The braches of trees were hollowed to make flutes.
Apollo left the instruments for the humans to find. Once they were found the natural curiousity of the humans took over. They picked them up and fiddled with them until the learned to make sounds pleasing to the ear. Soon enough the could combine the sounds of different instuments to make music.
Those who couldn't play the instruments learned to mock the sound with their voices; this became known as singing. eventually they grouped together to form bands. Music filled the land. This please the gods. Apollo soon became known as the God of music.