Wreaths, Hats, and Grain Measures
Roman gods wear a lot of stuff on their heads, especially wreaths/crowns. Here’s a quick overview for when sources mention iconography without explaining further.
Laurel Crown - Corona Triumphalis, Laurea Insignis: A triumphal crown of laurel or bay leaves, or a golden version thereof. Associated with Apollo.
Lunate diadem - Worn by Diana and Luna. The diadem in general is also used for goddesses as a mark of divinity, especially for Juno and Ceres.
Modius - Named by modern scholars, this headdress resembles a grain-measure and is presumed to symbolize abundance/fertility. Worn by Serapis.
Mural Crown - Corona Muralis: A crown bearing the city walls, commonly worn by Cybele and tutelary deities such as Tyche. A military version was awarded to the first man who scaled the wall of a besieged city.
Petasus - A flat hat worn by Mercury, originally a sign of travelers in Greek iconography.
Phrygian cap - Worn by “oriental” gods, either Trojan or simply foreign easterners. Typical of Attis, Mithras, Men, Sabazius, Ganymede, Paris, Orpheus, Aeneas, and Ascanius, among others. Its usage grew considerably in Late Antiquity and was picked up by some Christian iconography as well.
Pileus - A conical felt hat worn by the Dioscuri (Castor and Pollux), Vulcan, and occasionally Ulysses. Also worn by freedmen and thus symbolic of Libertas.
Spoked Crown - Corona Radiata: Radiant as though with the rays of the sun, this was the one given to the gods and deified heroes, and later assumed by some of the emperors as a token of their divinity. Associated with Sol Invictus.
Vine Crown - Corona Pampinea: The crown of vine leaves worn by Bacchus/Dionysus.
Wheat Crown - Corona Spicea: Made of ears of corn, consecrated to Ceres and among the most ancient of crowns (according to the Romans at least).
Grass Crown - Corona Graminea/Obsidionalis: Highest military honor, presented by a beleaguered army after its liberation to the general who broke up the siege. It was made of grass, or weeds and wild flowers gathered from the spot on which the beleaguered army had been enclosed.
Civic Crown - Corona Civica: Presented to a soldier who had preserved the life of a Roman soldier in battle. Made of oak leaves. Later assumed by the emperors and common in their iconography.
Stitched Crown - Corona Sutilis: Used by the Salii at their rites. Made of flowers sewn together instead of woven into a wreath. Later roses alone were used.
(Not included are Minerva’s helm, which is fairly recognizable on its own and doesn’t appear to have a specific name, and the many iterations of Isis’s headdresses, which I know too little of to parse. If anyone would like to add on the forms of Isis’s head gear, please feel free!)
