 Their end is marked by the consulship's disappearance under the reign of Justinian in 541.The oldest diptych that can properly be called a consular diptych, held in the cathedral treasury at Aosta, is one commissioned by Anicius Petronius Probus, consul in the Western Empire in 406 – it is unique not only for its extreme antiquity but also as the only one to bear the portrait of the Emperor (Honorius in this instance, to whom the diptych is dedicated in an inscription full of humility, with Probus calling himself the emperor's "" or slave) rather than that of the consul.Later, consular diptychs systematically carried either a more or less elaborate portrait of the consul on the most richly decorated examples or a dedicatory inscription to him within a geometric and vegetal scheme on the simpler examples.