Complex sentence: Acting on Ottoman orders Abu Dhahab then invaded Palestine to defeat Emir Daher, too, but after conquering Gaza, Jaffa (where he massacred the whole population) and Akko, he suddenly died because of the plague.
Split into simpler sentences: Acting on Ottoman orders Abu Dhahab then invaded Palestine to defeat Emir Daher, too. After conquering Gaza, Jaffa (where he massacred the whole population) and Akko, he suddenly died because of the plague.