Which Sultan was not a slave before he ascended the throne?

Qutub-ud-din Aibak, Iltutmish, and Balban were all originally slaves who belonged to the Mamluk (Slave) Dynasty and eventually rose to become Sultans. Alauddin Khilji, however, belonged to the Khilji Dynasty and was the nephew and son-in-law of Jalaluddin Khilji, the dynasty's founder; he was never a slave.