The general Festival of Juno Februa, meaning “Juno the purifier “or “the chaste Juno”, was celebrated on February 13–14. While Lupercalia was a festival local to the city of Rome.
“To abolish the heathens lewd superstitious custom of boys drawing the names of girls, in honour of their goddess Februata Juno, on the fifteenth of this month, several zealous pastors substituted the names of saints in billets, given on this day.”- Butler, Lives of the Fathers, Martyrs and Other Principal Saints London, 1756-59, quoted in Jack B. Oruch, “St. Valentine, Chaucer, and Spring in February”, Speculum 56.3 (July 1981, pp. 534-565), p 539.
“during a great art of the month of February…. in honour of Pan and Juno… On this occasion, amidst a variety of ceremonies, the names of young women were put into a box, from which they were drawn by the men as chance directed.” Douce repeated Butler’s description of the attempt to substitute saint’s names, and concluded that “as the festival of the Lupercalia had commenced about the middle of February, [the Christians] appear to have chosen Saint Valentine’s day for celebrating the new feast; because it occurred nearly at the same time”- Oruch 1981
“Valentinus of Rome was beheaded on the celebration day of the Roman God Juno, 14 Feb. 269 AD. Pope Gelasius created an official day of the church (St. Valentine’s Day, in memory of the priest) on 14 Feb. 496 AD.”