http://www.pbs.org/wgbh/pages/frontl...ecretum1.html\
"Because of his name and native land, St. Maurice had been portrayed as black ever since the 12th century. The insignia of the black head, in a great many instances, was probably meant to represent this soldier saint since a majority of the arms awarded were knightly or military. With 6,666 of his African compatriots, St. Maurice had chosen martyrdom rather than deny his allegiance to his Lord and Saviour, thereby creating for the Christian world an image of the Church Militant that was as impressive numerically as it was colourwise.
Here, no doubt, is a major reason why St. Maurice would become the champion of the old Roman church and an opposition symbol to the growing influence of Luther and Calvin. The fact that he was of the same race as the Ethiopian baptized by St. Philip in Acts of the Apostles was undoubtedly an important element to his significance as well. Since this figure from the New Testament was read as a personification of the Gentile world in its entirety, the complexion of St. Maurice and his Theban Legion (the number of which signified an infinite contingent) was also understood as a representation of the Church's universality - a dogmatic ideal no longer tolerated by the Reformation's nationalism. Furthermore, it cannot be coincidental that the most powerful of the German princes to remain within the Catholic fold, the archbishop Albrecht von Brandenburg, not only dedicated practically all the major institutions under his jurisdiction to St. Maurice but in what is today one of the most important paintings of the Renaissance, had himself portrayed in Sacred Conversation with him. Even more blatant was the action taken by Emanual Philibert, Duke of Savoy. In 1572 he organized the order of St. Maurice. The papal promulgation published at its institution declared quite unequivocally that the sole purpose for this knighthood was to combat of the Reformation. The order still exist exists although it has now combined with the Order of St. Lazarus. The white trefoiled cross of the combined order belongs to the former.
The particular symbol of St. Maurice's blackness that must have most antagonized the Protestant faction, however, was the one regarding the mystery of Papal authority. Scholars have been able to show, for example, that in the theological debates of this period, even the abstract adjectives, black and white, were defiantly acknowledged by apologists of both stripes to represent the Church and the Reformers respectively."