The basic insignia of the Order is a white-enamelled Maltese cross. The crowned Brandenburg (later, Prussian) eagles between the arms of the crosses date from 1668; they are gold for Knights of Justice, Honorary Commanders, Commanders, and the "Herrenmeister", but, on the crosses of Knights of Honour and Honorary Members, the eagles are enamelled black with only the tiny crowns on each eagle's head left unenamelled gold. The closed crown of the king of Prussia on the "Herrenmeister"s cross and the crosses of Commanders, Honorary Commanders, Knights of Justice, and Honorary Members dates from the time of Frederick the Great, when his government authorised it to be used on the insignia. Excluding the crown, the cross of a Knight of Justice is 5 cm in diameter; the cross of a Commander, Honorary Commander, or Honorary Member, 5.5 cm; and the cross of the "Herrenmeister", 7 cm The uncrowned cross of a Knight of Honour is 6 cm in diameter. Each cross is worn from a black-moire, 4.5-centimeter-wide ribbon worn about the neck.