Complex sentence: Ellenberger was born in Rhodesia of Swiss parents in a British colony; was naturalized French; and, under pressure from the Vichy government, emigrated to Switzerland in 1941.
Split into simpler sentences: Ellenberger was born in Rhodesia of Swiss parents in a British colony, and was subsequently naturalized French. Subsequently, under pressure from the Vichy government, Ellenberger emigrated to Switzerland in 1941.