Complex sentence: Romek Strzalkowski (1943-1956) was a 13 year old pupil killed by the communist Security Forces during anti-communist protests in Poznan 1956, he has became one of the best known symbols of anti-communist resistance in Poland.
Split into simpler sentences: Romek Strzalkowski (1943-1956) was a 13-year-old pupil killed by the communist Security Forces during anti-communist protests in Poznań in 1956. He has became one of the best-known symbols of anti-communist resistance in Poland.