Complex sentence: Kurt Aßmann (13 July 1883--26 July 1962) was a German admiral who was present at Adolf Hitler's Wolfsschanze headquarters on 20th July 1944, during the unsuccessful attempt on the German leader's life (known as the 20 July Plot).
Split into simpler sentences: Kurt Aßmann (13 July 1883--26 July 1962) was a German admiral. He was present at Adolf Hitler's Wolfsschanze headquarters on 20th July 1944, during the unsuccessful attempt on the German leader's life (known as the 20 July Plot).