Complex sentence: The battle ended with the defeat of the Christian troops, who returned to Toledo to defend themselves, but the Emir didn't took advantage of the victory, because he hurried back to Africa because of the death of his son.
Split into simpler sentences: The battle ended with the defeat of the Christian troops, who returned to Toledo to defend themselves. The Emir, however, did not take advantage of the victory since he had to rush back to Africa because of the death of his son.