The ability of the Mozarabs to assimilate into Moorish culture while maintaining their Christian faith has often caused them to be depicted by Western scholars as having a strong allegiance to Roman Catholicism and its cause. However, the historian Jaume Vicens Vives offers another view of the Mozarabs. He states that one of the Emperor Charlemagne's major offensives was to annihilate the Moorish frontier by taking Zaragoza, which was an important Mozarab stronghold. However, the offensive failed because the Mozarabs of the city refused to cooperate with the Catholic emperor. Vives concludes that the Mozarabs were primarily a self-absorbed group. They understood that they could gain a great deal by remaining in close contact with the Moors.