Al-Walid ibn Abd al-Malik ibn Marwan (c. 674 – 23 February 715), commonly known as al-Walid I, was the sixth Umayyad caliph, ruling from October 705 until his death in 715. He was the eldest son of his predecessor, Caliph Abd al-Malik (r. 685–705). As a prince, he led annual raids against the Byzantines from 695 to 698 and built or restored fortifications along the Syrian Desert route to Mecca. He became heir apparent in c. 705, after the death of the designated successor, Abd al-Malik's brother Abd al-Aziz ibn Marwan.
Under al-Walid, his father's efforts to centralize government, impose a more Arabic and Islamic character on the state, and expand its borders were continued. He heavily depended on al-Hajjaj ibn Yusuf, his father's powerful viceroy over the eastern half of the caliphate. During his reign, armies commissioned by al-Hajjaj conquered Sind and Transoxiana in the east, while the troops of Musa ibn Nusayr, the governor of Ifriqiya, conquered the Maghreb and Hispania in the west, bringing the caliphate to its largest territorial extent. War spoils from the conquests enabled al-Walid to finance impressive public works, including his greatest architectural achievement, the Great Mosque of Damascus, as well as the al-Aqsa Mosque in Jerusalem, the expansions of the Prophet's Mosque in Medina and the Great Mosque of Sana'a, and the building of the historical city of Anjar. He was the first caliph to institute programs for social welfare, aiding the poor and handicapped among the Muslim Arabs of Syria, who held him in high esteem.