In response to the invasion, the Franks began their campaign of reconquest. Following the Battle of Poitiers in 732, the Saracens gradually abandoned the south of France, pursued by Charles Martel. In 737, after Martel's failure to reconquer Septimania, he destroyed the first cathedral at Maguelone which had been converted into a mosque by the Saracens. The architecture of the original building remains unknown.