A disciple of Vishvamitra, who demanded from him as a fee, Guru Dakshina, eighthundred white horses with one black ear.
Galava went to four kings to request the horses. The first gave him his daughter, Madhavi. He got 200 horses each from three other kings, in return, each king fathered a son with Madhavi. For the missing 200 horses he gave Madhavi to Vishvamitra, who also fathered a son with her.
See Richika, he also had to find white horses with a black ear.
Read the story here
http://sushmajee.com/biographies/bio-E-H/gaalav.htm
There is another myth about Galava in which he is Vishvamitra’s son. Vishvamitra withdrew into the forest. During this time his wife and sons suffered from a drought. She sold a son. The buyer put a rope around his neck (Gala) and took him to the market. He was ransomed and brought back to the family.