Ibn Abi Mulaykah narrates: the Prophet (peace and blessings be upon him) asked Abu Bakr (may Allah be pleased with him) for the hand of Sayyidah Aishah (may Allah be pleased with her), while Abu Bakr (may Allah be pleased with him) had earlier given her in marriage to Jubayr bin Mut'im. So he had that marriage dissolved and gave her in marriage to the Messenger of Allah (peace and blessings be upon him), and at that time she was six years old. He (peace and blessings be upon him) left her for three years, then consummated the marriage with her when she was nine years old.
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 19367