Complex sentence: Rivalled by the Welf scion Otto IV, Philip was able to stable his rule over the German kingdom, however, on 21 June 1208 he was killed by the Bavarian count palatine Otto VIII of Wittelsbach, leaving Irene widowed a second time.
Split into simpler sentences: Rivalled by the Welf scion Otto IV, Philip was able to stable his rule over the German kingdom. On 21 June 1208, he was killed by the Bavarian Count Palatine Otto VIII of Wittelsbach, leaving Irene widowed a second time.