Fatah is a Palestinian nationalist political party. Fatah is an acronym for Harakat At-Tahriri Al-Filistiniya. That means Palestinian National Liberation Movement in English. It was created by Yasser Arafat in the late 1950s.
In 1968 Fatah joined the Palestinian Liberation Organization, and in 1969 it got a leadership role. When it was founded, it did not accept the existence of Israel, but now the group officially does.