After the pact of Hudaibiya, the truth dawned on 'Amr b Al-Aas and he hastened to Madina along with Khalid b Walid where they accepted Islam. After conversion to Islam, 'Amr b Al-Aas proved to be a great asset for Islam. The Holy Prophet entrusted him with some important missions which he fulfilled successfully; Later the Holy Prophet appointed him as the Governor of Oman. After the death of the Holy Prophet, when Abu Bakr became the Caliph he was recalled from Oman to lead campaigns against some of the apostate tribes. After the end of the apostasy wars he was commissioned to undertake campaigns in Palestine and Syria. During the Caliphate of Umar he invaded Egypt and conquered it. In the history of Islam he enjoys fame as the "Conqueror of Egypt". Umar appointed him as the Governor of Egypt. When Othman became the Caliph, he allowed 'Amr to continue as the Governor of Egypt for some time. Later 'Amr was deposed and Othman appointed his foster brother as the Governor of Egypt.
"When a person dies, his works end, except for three: ongoing charity, knowledge that is benefited from, and a righteous child who prays for him."
Prophet Mohammed (PBUH)
"The best of what a man leaves behind are three: a righteous child who supplicates for him, ongoing charity the reward of which reaches him, and knowledge that is acted upon after him."
Sunan Ibn Mājah
"Every day two angels come down from Heaven and one of them says, 'O Allah! Compensate every person who spends in Your Cause,' and the other (angel) says, 'O Allah! Destroy every miser.'"
Sahih Bukhari