Complex sentence: Ruled by the Aksumites (Semitic people of Ethiopia-Amharas and Tigrawai/Tigre are the most notable ones), it existed from approximately 100 AD to 940 AD.
Split into simpler sentences: Ruled by the Aksumites (Semitic people of Ethiopia-Amharas and Tigrawai/Tigre are the most notable ones). It existed from approximately 100 AD to 940 AD.