The Establishment of the Al Sauds
Muhammad ibn abd al-Wahhab
Unknown
1844: Islamic preacher Muhammad ibn abd al-Wahhab arrived in Arabia, formed alliance with Al-Sauds
"Upon their meeting, the two made the covenant wherein Mohammed ibn Saud would help Muhammed ibn Abdul-Wahhab to spread his religious teachings" and Wahhab gave the Al Saud rule religious legitimacy (The Arab Gulf States Institute in Washington)
Abdul Aziz and brothers (Al Saud family) defeated other groups fighting for land (Rahids, Hashemites, Ottomans & more) by capturing Riyadh (Saudi Arabia capital) in 1902 and Mecca and Medina (Islamic Holy Cities) in mid-1920's.