This ruler's armies, commanded by his son, were defeated at the Battle of Syllaeum, where Greek fire decimated his troops and forced an unfavorable treaty with Constantine IV.
This ruler's armies, commanded by his son, were defeated at the Battle of Syllaeum, where Greek fire decimated his troops and forced an unfavorable treaty with Constantine IV. He had impressive lineage as the son of Hind bint Utbah and Abu Sufyan, but his succession by his own son Yazid I is often seen as a violation of his treaty with Hasan, who agreed to let this man rule after the Kharijites had assassinated Hasan's  ►father Ali. FTP, name this caliph from 661-680 AD, the founder of the Umayyad Dynasty. 
This ruler's armies, commanded by his son, were defeated at the Battle of Syllaeum, where Greek fire decimated his troops and forced an unfavorable treaty with Constantine IV.
Muawiyah (Mu'awiyah ibn Abi Sufyan or Muawiyah I)    