Complex sentence: When freed slaves and other descendants of Afro-American people began returning to the African continent, mainly in the western part many overseas-controlled churches were abandoned by a great number of Africans, and independent churches were founded.
Split into simpler sentences: When freed slaves and other descendants of Afro-American people began returning to the African continent, mainly in the western part. Many overseas controlled churches were abandoned by a great number of Africans, and independent churches were founded.