Bánk bán is an opera in 3 acts by composer Ferenc Erkel. The work uses a Hungarian-language libretto by Béni Egressy which is based on a stage play of the same name by József Katona. The main storyline is based on the assassination of Queen Gertrude, wife of Andrew II in 1213. The opera was first performed at the Pesti Nemzeti Magyar Szinház in Pest on 9 March 1861.