Assertion: umayyad caliph | /r/HasProperty | muawiyah i
Facets:
Source sentences:
text: Hostilities only ceased when Ali's eldest son Hasan (who had been elected upon his father's death) made an agreement to abdicate in favour of the first Umayyad caliph, Muawiyah I, resulting in a period of relative calm and a hiatus in sectarian disagreements.