Complex sentence: Chilembwe sought social, economic and political advancement for Africans, and his frustration at their being denied an effective voice, and anger over African casualties in the First World War moved him from peaceful protest to a violent uprising in 1915.
Split into simpler sentences: Chilembwe sought social, economic and political advancement for Africans. His frustration at Africans being denied an effective voice and anger over African casualties in the First World War moved him from peaceful protest to a violent uprising in 1915.