The presence of Arabic words and names in Latin documents preserved in monasteries in the northern kingdoms of the Iberian Peninsula from the ninth to the eleventh century, has given rise to investigation on two fronts. First, they are sufficiently arresting as to promote theories concerning their origin. Secondly, and more problematically, the impact on both the ecclesiastical and secular society of those who bear Arab names has invited analysis. It has been customary to see in the incidence of these names in Latin documents, evidence of Arabic influence in the Christian regions of the north of the Peninsula. That is to say, those who had these Arab names contributed to the emergence of what has come to be regarded as the Mozarabic period. Yet it is by no means unequivocally clear what such contributions were or might have been, and further, there is unimpeachable evidence that some of those responsible for bringing about the ‘age’ of Mozarabism were not themselves Arabicized. What is discussed in this chapter is an attempt to throw light on these issues.