According to the Shia and Sunni versions of the Islamic eschatology the Mahdi (also Mehdi; "Guided One")'s the prophesied redeemer of Islam who'll stay on earth seven, nine, or nineteen years (depending on the interpretation) before the coming of the day, Yaum al-Qiyamah (literally "Day of the Resurrection" or "Day of the Standing"). The concept of Mahdi isn't explicitly mentioned in the Qu'ran nor in the Sunni hadiths such as Sahih al-Bukhari which only mention the second coming of Jesus. It's… (More on Mahdi)