The Houthi group grew from a Zaydi revivalist movement established in the mid-1990s by Hussein Badr Al-Din Al-Houthi, known as Al-Shabab Al-Muminin (The Believing Youth). The Zaydi branch of Islam is named after Zayd Ibn Ali, grandson of Hussein Ibn Ali, the third Shiite imam. A Zaydi state was established in northern Yemen in 893 by one of his descendants, Yahya Ibn Hussein, who arrived in Sadah from Medina. The imamate persisted until 1962; the last imam, Al-Badr Muhammad Bin Ahmed Hamid Al-Din, died in London in 1996.