Complex sentence: The Pechenegs destroyed the Hungarians' dwelling places, therefore those who survived the double attack decided to leave the Pontic steppes and cross the Carpathian Mountains in search for a new homeland.
Split into simpler sentences: The Pechenegs destroyed the Hungarians' dwelling places. Those who survived the double attack decided to leave the Pontic steppes and cross the Carpathian Mountains in search for a new homeland.