Mother of Mountains

The Mother of Mountains is a mountain in Essos. It is considered sacred to the Dothraki.

Season 1
During his vow to take the Iron Throne for his unborn son, Rhaego, Khal Drogo swears by the Mother of Mountains.

In the books
In the A Song of Ice and Fire books, the Mother of Mountains is a mountain sacred to the Dohtraki people, located within sight of Vaes Dothrak and a lake known as the Womb of the World, from which, according to myth, the first man emerged riding on the first horse. Only men are allowed to set foot on the Mother of Mountains.