The identity of the heraldic writer Johannes de Bado Aureo is a matter of dispute.
His work, Tractatus de armis, written at the behest of the late Anne of Bohemia (died 1394), consort of Richard II, appeared first in a Latin manuscript that is conventionally dated from the wording of the dedication c.1395.
Johannes broke with previous tradition in denying the right of a man-at-arms to assume a coat of arms.
Sir Edward Bysshe published both treatises as Nicholai Vptoni, de Stvdio Militari, Libri Quatuor, Johan.
Professor Evan John Jones, in Medieval Heraldry: Some Fourteenth Century Heraldic Works (Cardiff: William Lewis, Ltd.) 1943, suggested that "Johannes de Bado Aureo" may have been Bishop Sion Trevor, an ecclesiastic who was trained in Roman law, and rose through the Church hierarchy to become Bishop of St Asaph, Wales.