Simplify the following text for a Grade 8 native English-speaking person.
Original: The Songhai had long been a major power in West Africa subject to the Mali Empire 's rule . In the late 14th century , the Songhai gradually gained independence from the Mali Empire and expanded , ultimately subsuming the entire eastern portion of the Mali Empire .
Simplified: These kingdoms included the Ghana Empire , the Mali Empire , and the Songhai Empire .