Baltic songs marry the Moon to the Sun. He falls for the morning star, and the thunder god takes a sword to him — which is what the phases are.

Mėnulis and Saulė are among the best-attested figures in Baltic mythology because the folk songs survived so late and were collected so thoroughly. Perkūnas cutting the Moon is one of the more direct mythological accounts of why the disc changes shape, and it is repeated in Latvian versions almost word for word.