Answer
Al-Malik al-Zahir Rukn al-Din Baybars al-Bunduqdari was the founder and first sultan of the Mamluk Bahri Sultanate. He was born into slavery in 1223, and rose to become a Mamluk commander in the service of the Ayyubid sultan of Egypt, al-Salih Ayyub. After al-Salih Ayyub was killed in 1249, Baybars led the Mamluk army to victory against the invading Seventh Crusade, and became sultan himself in 1260.