Complex sentence: After the many failed Ottoman expeditions into Albania, Sultan Murad II decided to march an army into Skanderbeg's dominions to capture the key Albanian fortress of Svetigrad, near the modern city of Debar.
Split into simpler sentences: After the many failed Ottoman expeditions into Albania, Sultan Murad II decided to march an army into Skanderbeg's dominions to capture a key Albanian point. The main goal of this campaign was to capture the fortress of Svetigrad, near the modern city of Debar.