ABU BAKR ابو بكر
Of the origin of his name, there are various explanations. Some think that it means “the father of the maiden,” and that he received this title because he was the father of ‘Ayishah, whom Muhammad married when she was only nine years old. His original name was ‘Abd ‘l-Ka’bah (which the Prophet changed into ‘Abdu ‘llah) Ibn Abi Quhafah. He was the first Khalifah, or successor of Muhammad. [SHI'AH] Muslim writers praise him for the purity of his life, and call him as-Siddiq, the Veracious. He only reigned two years, and died August 22nd, A.D. 634.

Based on Hughes, Dictionary of Islam