She was born in
Mecca, the fifth of their six children. She was legally married before August 610 to
Utaybah ibn Abi Lahab, but the marriage was never consummated. She was still living with her parents when Muhammad was declared a prophet by God, and Umm Kulthum became a
Muslim soon after her mother did. Muhammad
left Mecca in September 622. Before long
Zayd ibn Haritha brought instructions to Umm Kulthum and her sister
Fatima to join their father in
Medina. However, Umm Kulthum and Fatima arrived safely in Medina. ==Second marriage==