Valmiki was going to the river Ganga for his daily ablutions. A disciple by the name Bharadwaja was carrying his clothes. On the way, they came across the Tamasa Stream. Looking at the stream, Valmiki said to his disciple, "Look, how clear is this water, like the mind of a good man! I will bathe here today." When he was looking for a suitable place to step into the stream, he heard the sweet chirping of birds. Looking up, he saw two birds flying together. Valmiki felt very pleased on seeing the happy birds. Suddenly, one of the birds fell down, hit by an arrow; it was the male bird. Seeing the wounded one, its mate screamed in agony. Valmiki's heart melted at this pitiful sight. He looked around to find out who had shot the bird. He saw a hunter with a bow and arrows, nearby. Valmiki became very angry. His lips opened and he uttered the following words:
You will find no rest for the long years of Eternity
For you killed a bird in love and unsuspecting
Emerging spontaneously from his rage and grief, this was the first œloka in Sanskrit literature. Later Valmiki composed the entire Ramayana with the blessings of Lord Brahma in the same meter that issued forth from him as the œloka
http://en.wikipedia.org/wiki/Valmiki