The Lemuralia or Lemuria was a feast in the religion of ancient Rome during which the Romans performed rites to exorcise the malevolent and fearful ghosts of the dead from their homes. The unwholesome spectres of the restless dead, the lemures or larvae were propitiated with offerings of beans. On those days, the Vestals would prepare sacred mola salsa, a salted flour cake, from the first ears of wheat of the season.
In the Julian calendar the three days of the feast were 9, 11, and 13 May. The origin myth of this ancient festival, according to Ovid, who derives Lemuria from a supposed Remuria was that it had been instituted by Romulus to appease the spirit of Remus (Ovid, Fasti, V.421ff; Porphyrius). Ovid notes that at this festival it was the custom to appease or expel the evil spirits by walking barefoot and throwing black beans over the shoulder at night. It was the head of the household who was responsible for getting up at midnight and walking around the house with bare feet throwing out black beans and repeating the incantation, "I send these; with these beans I redeem me and mine" (Haec ego mitto; his redimo meque meosque fabis.) nine times. The household would then clash bronze pots while repeating, "Ghosts of my fathers and ancestors, be gone!" nine times.
Because of this annual exorcism of the noxious spirits of the dead, the whole month of May was rendered unlucky for marriages, whence the proverb Mense Maio malae nubent ("They wed ill who wed in May").
On what had been the culminating day of the Lemuralia, May 13 in 609 or 610— the day being recorded as more significant than the year—, Pope Boniface IV consecrated the Pantheon at Rome to the Blessed Virgin and all the martyrs, and the feast of that dedicatio Sanctae Mariae ad Martyres has been celebrated at Rome ever since.