"The power of the Goths, who had held Spain for three centuries, was shattered at the battle of Jerez de la Frontera in 711, and almost immediately the Moors became masters of Spain and so remained for five hundred years, and masters of Granada for a much longer period. Until 850 the Christians were... free as to religion and... holding political office, so that priests and monks were not infrequently skilled... in Latin and Arabic, acting as official translators... [W]hile it lasted the learning and the customs of the East must have be come more or less the property of Christian Spain. At thie time the ġobār numerals were probably in that country, and these may well have made their way into Europe from the schools of Cordova, Granada, and Toledo."