There are several instances during the succeeding centuries of this ceremonial presentation of a flag by high ecclesiastical authorities to the leaders of expeditions whose aims received the approval of the Church, the most important, from our point of view, being the presentation made to William the Conqueror before his expedition to England. Beside these there appear to have been other flags in use which symbolised the patronage and protection of some especial saint, as for instance the vexillum of St Maurice borne in the Spanish campaigns of Charlemagne. It seems probable that the laterally-attached form of flag had its origin in the East, for Ximenes de Rada, Archbishop of Toledo, who died in 1247, mentions this form as one of the special characteristics of the Arabs who overcame Roderic in 711 A.D. and conquered Spain[34]. It is true that, as will be seen in the next chapter, the Danes were using this form in the ninth century, but it is more probable that they had adopted it from the Franks than that they had invented it; certainly the only standards of the Germanic tribes known to the Romans were animal emblems, which were kept in the sacred groves until required in battle[35]. The form of flag that first comes into evidence in the Lateran mosaic, that in which the flag is attached laterally to the staff while the fly is cut into three pointed tails, appears again upon two Carlovingian book-covers of carved ivory, one of the ninth and one of the tenth century, now preserved in South Kensington Museum. Neither of these bears any device upon it, but in another book-cover of the twelfth century in the same collection a small cross saltire appears in the body of the flag, and the tails are proportionately of much greater length. This form, to which the term "gonfanon" became applied, was the principal form in use until the twelfth century, when it began to be replaced by the rectangular banner, which offered a more suitable field for the display of the personal devices that afterwards developed into heraldic charges.