GUILLEM, JOHN, of Welsh extraction, was born in Herefordshire about the year 1565. Having completed his education at Brazen-nose College, Oxford, he became a member of the College of Arms in London; and he was made rouge-croix pursuing, in which post he died in 1621. He published, in 1610, a work entitled the Display of Heraldry, folio, which has gone through many editions. To the fifth, which appeared in 1679, was added a Treatise of Honour Civil and Military, by Captain John Logan.