Battle of Marj Rahit: Umayyad partisans defeat the supporters of Ibn al-Zubayr and cement Umayyad control of Syria.

The Battle of Marj Rahit was one of the early battles of the Second Fitna. It was fought on 18 August 684 between the Kalb-dominated armies of the Yaman tribal confederation, supporting the Umayyads under Caliph Marwan I, and the Qays under al-Dahhak ibn Qays al-Fihri, who supported the Mecca-based Abdallah ibn al-Zubayr; the latter had proclaimed himself Caliph. The Kalbi victory consolidated the position of the Umayyads over Bilad al-Sham, paving the way for their eventual victory in the war against Ibn al-Zubayr. However, it also left a bitter legacy of division and rivalry between the Qays and the Yaman, which would be a constant source of strife and instability for the remainder of the Umayyad Caliphate.

August 18 is the 230th day of the year in the Gregorian calendar; 135 days remain until the end of the year.

The Umayyad Caliphate or Umayyad Empire was the second caliphate established after the death of the Islamic prophet Muhammad and was ruled by the Umayyad dynasty. Uthman ibn Affan, the third of the Rashidun caliphs, was also a member of the clan. The family established dynastic, hereditary rule with Mu'awiya I, the long-time governor of Greater Syria, who became caliph after the end of the First Fitna in 661. After Mu'awiya's death in 680, conflicts over the succession resulted in the Second Fitna, and power eventually fell to Marwan I, from another branch of the clan. Syria remained the Umayyads' main power base thereafter, with Damascus as their capital.

Abd Allah ibn al-Zubayr ibn al-Awwam was the leader of a caliphate based in Mecca that rivaled the Umayyads from 683 until his death.