Complex sentence: He met the Muslim forces again near the river Orbieux, at Villedaigne, where he was defeated, though his obstinate resistance exhausted the Muslim forces so much that they retreated to Spain.
Split into simpler sentences: He met the Muslim forces again near the river Orbieux, at Villedaigne, where he was defeated. However only after an obstinate resistance which exhausted the Muslim forces so much that they retreated to Spain.