Complex sentence: Metaxas never saw the German invasion of Greece during the Battle of Greece because he died in Athens on 29 January 1941, of a phlegmon of the pharynx which subsequently led to incurable toxaemia.
Split into simpler sentences: Metaxas never saw the German invasion of Greece during the Battle of Greece because he died in Athens on 29 January 1941. Metaxas died of a phlegmon of the pharynx which subsequently led to incurable toxaemia.