Excerpts from Books and Wikipedia
"Muslim recovery was begun by Zangi, the emir of Mosul who recaptured Edessa from the crusaders in 1144 and his son Nur al-din, who united Syria under this rule in 1154 and conquered Egypt in 1169. . . . Nur al-Din continued to rule from Mosul and sent the Kurdish general Saladin to Egypt as his viceroy. . . . Nur al-Din was preparing for war against Saladin when he died at Damascus on May 15, 1174. . . . Saladin, however, claimed to be the rightful regent. In late October he seized Damascus and proclaimed himself sultan, reinforcing his authority by marrying Nur al-Din's widow. . . . Saladin was widely regarded as a usurper for his callous actions, but his success in recapturing Jerusalem from the crusaders in 1187 easily counterbalanced this train of thought and made him a hero in the Muslim world." [1001 Days]