Umar ibn al-Khattab

Born: c. 586 in Makkah, Arabia
Died: November 3, 644 (23 AH) in Medina, Arabia (assassinated by a Persian traitor.)
Caliph: 634 - 644

Umar, may God be pleased with him, was the second successor, or caliph, to the Prophet Muhammad, peace be upon him.

Initially, he had opposed Islam and, when he heard that his sister and her husband had converted, he went to admonish them. According to tradition, though, he allowed them to recite verses from the Qur'an for him and converted on the spot.

After the death of the Prophet, Umar made sure that the leadership went to Abu Bakr, an effort which helped ensure that the Muslims remained in unity.

Umar was the one who determined that the year of the Hijra, the Migration of the Prophet from Makkah to Medina, would be the first year of a new Islamic calendar and he organized the expanding territories conquered by Muslim forces.

Indeed, it was under Umar's leadership that Islam made its largest and fastest expansion. During his reign Muslim forces conquered Syria, Jerusalem, Egypt, Libya, Iraq, and the armies of Persia. When Muslims look back upon a Golden Age of Islam, this is usually the era they have in mind - this is when Islam was making its biggest gains.