Complex sentence: However, he must have known of the African American exodus to the North, known as The Great Migration, in part to escape Jim Crow laws, disfranchisement, unemployment, lynchings, and mob violence.
Split into simpler sentences: However, he must have known of African Americans exodus northwards from the south, known as The Great Migration. Blacks in the deep South suffered through Jim Crow laws, disenfranchisement, unemployment, lynchings, and mob violence.