 Iltutmish refused to oblige, defeating and killing Yildiz at the Battle of Tarain in 1216.He also fought with Nasir ad-Din Qabacha, another former Ghuird slave, for control of Lahore.In 1221, a Mongol invasion prompted the Khwarazmian ruler Jalal ad-Din Mingburnu to move to the Indus Valley region, which became embroiled in conflicts involving Jalal ad-Din, Qabacha, and the Mongols.