Behind Ansar Allah’s surprising geopolitical gains stands an ancient religious tradition. Zaydism is one of the 3 surviving major branches of Shia Islam, alongside Twelverism and Ismailism. Twelverism—the dominant branch, comprising the majority of Shia Muslims worldwide and the state religion of Iran—holds that authority passed through a line of 12 divinely appointed Imams, the last of whom went into occultation in 874 CE and is expected to return as a messianic figure at the end of times. Ismailism, sometimes called Sevener Shia, split from the Twelver line over which son of the sixth Imam was the rightful successor; its most prominent surviving branch today follows the Aga Khan as the living Imam
