March 24
ante diem ix kalendas aprilesFestival of Mars
Dies sanguinis - The last of nine days of fasting in honor of Cybele. Devotees of the goddess Cybele would practice self-flagellation on this day. It may be the origin of Good Friday.
Calendars were marked QRCF (Quando Rex Comitavit Fas) although it's not known what this was for.
This and the previous day were the only days the comitia calata met to sanction wills.
Day of Blood - Dies Sanguinis
In ancient Roman history, the 24th of March (VIII Kal Apriles) was the Dies sanguinis 'day of blood,' possibly a precursor of Good Friday. 
On the 22 of March, the arbor intrat, a procession of palms or a pine tree was brought to the shrine of Cybele. Two days later, at the Day of the Blood, the priests of Cybele slashed themselves and spun around to sprinkle her statue with blood. Afterward, the priests washed the statue in the Almo River, a Tiber tributary. This was not one of the ancient holidays celebrated ever since the legendary period, but one from the imperial period.
Jacob Latham writes that the most accepted version of ancient events is that in the 1st century A.D., a time when the number of festivals to Attis was increasing, funereal rites were introduced, including the arbor intrat of March 22 (to March 23, since there was an all-night vigil) introduced under Emperor Claudius (41-54), and the March 24th dies sanguinis, when devotees may have castrated themselves, but more likely flagellated and slashed themselves to offer blood to the goddess. Then, under the Emperor Antoninus Pius (138-61), another festival was added, on March 15 (the fateful Ides) called the canna intrat, which was a procession of reeds, and, possibly under the same emperor or later, another festival known as the hilaria, "a masked carnival marked by licentious behavior."
Duncan Fishwick writes: "...24th March was the dies sanguinis, the climactic point in the festival of Magna Mater. Apparently, under Claudius the old ' Roman' Megalesia (4th to 10th April) was replaced by a new festival of ' Phrygian ' character, which, by the third and fourth centuries, at least celebrated the death and resurrection of Attis."
For more information, please consult:
- Francis Redding Walton, John Scheid "Cybele" The Oxford Classical Dictionary .
- "Hastiferi"
Duncan Fishwick
The Journal of Roman Studies, Vol. 57, No. 1/2 (1967), pp. 142-160 - "The Cannophori and the March Festival of Magna Mater"
Duncan Fishwick
Transactions and Proceedings of the American Philological Association, Vol. 97 (1966), pp. 193-202 -
"Attis: A Greek God in Anatolian Pessinous and Catullan Rome"
Jan N. Bremmer
Mnemosyne, Fourth Series, Vol. 57, Fasc. 5, Catullus 63 (2004), pp. 534-573 - "'Fabulous Clap-Trap': Roman Masculinity, the Cult of Magna Mater, and Literary Constructions of the galli at Rome from the Late Republic to Late Antiquity"
Jacob Latham
The Journal of Religion, Vol. 92, No. 1 (January 2012), pp. 84-122
March Fasti
This Day in HistoryDaily Features
