Lupercalia
The Luperci ran around the Palatine striking onlookers with goatskin thongs in an old purification rite.
Background
The Lupercalia was one of Rome's oldest and strangest festivals, centred on the Lupercal, the cave at the foot of the Palatine where, in legend, a she-wolf nursed Romulus and Remus tradition. Its rites were already ancient and puzzling to Romans of the late Republic.
On 15 February the Luperci, young men in two colleges, sacrificed goats and a dog at the cave. Two youths were touched on the forehead with the bloody knife, wiped clean with wool soaked in milk, and had to laugh per Plutarch. The Luperci, nearly naked and wearing goatskins, then ran around the Palatine striking people with thongs cut from the hides. Women offered their hands to be struck, believing it would help them conceive and give birth per Ovid and Plutarch.
In 44 BC, at the Lupercalia, Mark Antony, running as a Lupercus, offered Julius Caesar a royal diadem, which Caesar refused before the crowd; a month later Caesar was dead. The festival survived long into the Christian era; Pope Gelasius I argued against it in the late 5th century per his letter to Andromachus.
