Uthman (Third Caliph/successor of the prophet) was hacked to pieces by his opposition. That marked the beginning of Caliphite of Ali
Ali (Fourth Caliph) was killed stepping out of the mosque. That marked the beginning of the rule of Umayyads.
Hussein was massacred by the Umayyads. That breathed a new life into the Shia sect.
Marwan (The fourteen and last Umayyads Caliph) was decapitated which marked the beginning of Abbasid. Twelve thousand troops of Umayyads were destroyed by the hands of their Muslim brothers the Abbasids.
In our Islamic history change in power is tied to violence. Could it be that we do not read our history?