The helmet appears on coins; as in those of Macedon under the Romans, which have a head of Alexander, sometimes covered with a helmet. Probus also has often the helmet on his coins; and Constantine the first, has helmets of different forms curiously ornamented. THE NIMBUS OR GLORY. The nimbus or glory, now peculiar to the saints, was formerly applied to emperors. A nimbus appears round the head of Constantine the second, in a gold coin of that prince; and of Flavia Maxima Fausta, in a gold medallion; and of Justinian in another. But the idea is as ancient as the reign of Augustus, and is found in Roman authors, before it appeared on coins. Oiselius gives a coin of Antoninus Pius, with the _nimbus_, but this however is doubtful, and may have been some flaw in the coin from which he engraved his representation. OTHER ORNAMENTS OF THE HEAD. Besides the diadem, the Greek princes sometimes appear with the laurel crown. The Arsacidæ, or kings of Parthia, wear a kind of sash round the head, with their hair in rows of curls like a wig. Tigranes and the kings of Armenia, wear the _tiara_, a singular kind of cap, but the well known badge of imperial power in the ancient eastern world. Xerxes, a petty prince of Armenia, appears in a coin extant of him in a conical cap, with a diadem around it. Juba, the father, has a singular crown, like a conical cap, all hung with pearls. The successors of Alexander assumed by way of distinction, different symbols of the Deity, to be observed on the busts of their medals, such as the lion’s skin of Hercules, which surrounds the head of the first Seleucus; the horn placed behind the ear, an image of their strength and power, or of their being the successors of Alexander, called the son of Jupiter Ammon; the wing placed in like manner behind the ear, symbolic of the rapidity of their conquests, or of their being descendants from the god Mercury. Some authors, however, have doubted if all these heads be not of gods, except those with the horn. Eckhel observes, that even the horn and diadem belong to Bacchus, as on a coin of Nuceria Alfaterna. Bacchus, according to Diodorus Siculus, invented the diadem, to cure his head-aches, and was horned like his father Jupiter Ammon. The only king who appears on coins, according to Eckhel, with the horn, is Lysimachus. Pyrrhus had a crest of goats’ horns to his helmet, as we are informed by Plutarch, in his life, and the goat was the symbol of Macedon. It is likely that the successors of Alexander took this badge of the horn in consequence.