Complex sentence: Abu Abdallah Mohammed II, Al-Mutawakkil, often simply Abdallah Mohammed (died 4 August 1578, reigned 1574--1576) was the oldest son of Abdallah al-Ghalib and became the sultan of Morocco after his father's death.
Split into simpler sentences: Abu Abdallah Mohammed II, Al-Mutawakkil, often simply Abdallah Mohammed (died 4 August 1578) was Sultan of Morocco from 1574 to 1576. He was the oldest son of Abdallah al-Ghalib and became Sultan after his father's death.