In the earliest period, arms were assumed by their bearers without any need for heraldic authority. However, by the middle of the fourteenth century, the principle that only a single individual was entitled to bear a particular coat of arms was generally accepted, and disputes over the ownership of arms seems to have led to gradual establishment of heraldic authorities to regulate their use. The earliest known work of heraldic jurisprudence, "De Insigniis et Armis", was written about 1350 by Bartolus de Saxoferrato, a professor of law at the University of Padua. The most celebrated armorial dispute in English heraldry is that of "Scrope v Grosvenor" (1390), in which two different men claimed the right to bear "azure, a bend or". The continued proliferation of arms, and the number of disputes arising from different men assuming the same arms, led Henry V to issue a proclamation in 1419, forbidding all those who had not borne arms at the Battle of Agincourt from assuming arms, except by inheritance or a grant from the crown.