Mastorava

Mastorava () is a Mordvin epic poem compiled based on Mordvin mythology and folklore by Aleksandr Sharonov, published in 1994 in the Erzya language, with a Moksha language version announced.
The poem consists of five parts entitled "The Universe", "Antiquity", "King Tyushtya's Age", "The Heroic Age" and "The New Age". "Mastorava" is an Earth goddess in Mordvin mythology. The name "mastor-ava" literally means "earth woman", "mastor" being the Mordvin for "earth, land".
In the Mastorava epic, Tyushtya is a peasant elected by people to be the king and leader of Mokshan and Erzyan clans alliance and the warlord of allied army. During his rule, Mordvinia stretched from Volga to Dnieper and from the Oka to the Black Sea. 
In Mordvin mythology, Tyushtya is a moon god, son of the thunder god and the mortal girl Litova. He changes his age every month, following the phases of the Moon.