Complex sentence: Frederick III or IV (1 September, 1341--27 January, 1377), called the Simple, King of Sicily from 1355 to 1377, was the second son of Peter II of Sicily and Elisabeth of Carinthia.
Split into simpler sentences: Frederick III or IV (1 September, 1341--27 January, 1377), called the Simple was King of Sicily from 1355 to 1377. He was the second son of Peter II of Sicily and Elisabeth of Carinthia.