Before the success of Tarzan, Burroughs led a life full of failures. The turning point came when he started to write for pulps at the age of 35 - firmly convinced that he could write as rotten stuff as published in pulp fiction magazines. His first professional sale was Under the Moons of Mars, serialized in 1912 and later published as the novel A Princess of Mars which introduced the popular invincible hero John Carter, who is transported to Mars apparently by astral projection, following a battle with Apaches in Arizona. There, Carter proceeded to become embroiled in the politics and wars of Mars. Eventually he succeeded in winning the hand of his love, Dejah Thoris, Princess of Heluim. The 'Martian Tales' series eventually reached eleven books. The last book published posthumously, also contains a story by Burroughs' son, John Coleman Burroughs.