in antiquity, feasts celebrated every year by the Romans on the 8th of the kalends of April, or the 25th of March, in honour of Cybele the mother of the gods.
The hilaria were solemnized with great pomp and rejoicing. Every person dressed himself as he pleased, and took the marks or badges of whatever dignity or quality he had a fancy for. The statue of the goddess was carried in procession through the streets of the city, accompanied by multitudes in the most splendid attire. The day before the festival was spent in tears and mourning. Cybele represented the earth, which at this time of the year begins to feel the kindly warmth of the spring; so that this sudden transition from sorrow to joy was an emblem of the vicissitude of the seasons, which succeed one another.
The Romans took this feast originally from the Greeks, who called it κακοσέας, q. d. acerbus; the eve of that day they spent in tears and lamentations, and thence denominated it κακοσέας, defecus.
Afterwards, the Greeks took the name hagia from the Romans; as appears from Photius, in his extract of the life of the philosopher Hidore.
Cafabon maintains, that beside this particular signification, the word hilaria was also a general name for any joyful or festival day, whether public or private and domestic. But Salmasius does not allow of this.
Tristan, tom. i. p. 482, distinguishes between hilaria and hilarie. The former, according to him, were public rejoicings; and the latter, prayers made in consequence thereof; or even of any private feast or rejoicing, as a marriage, &c. The public lasted several days; during which, all mourning and funeral ceremonies were suspended.