Complex sentence: Ryszard Siwiec (7 March 1909--12 September 1968) was a Polish accountant and former Home Army resistance member who was the first person to commit suicide by self-immolation in protest against the Soviet-led invasion of Czechoslovakia.
Split into simpler sentences: Ryszard Siwiec (7 March 1909--12 September 1968) was a Polish accountant by profession, and former Home Army resistance member. He was the first person to commit suicide by self-immolation in protest against the Soviet-led invasion of Czechoslovakia.