Saint Valentine

The origin of St. Valentine, and how many St. Valentines there were, remains a mystery. One opinion is that he was a Roman martyred for refusing to give up his Christian faith. Other historians hold that St. Valentine was a temple priest jailed for defiance during the reign of Claudius. Whoever he was, Valentine really existed because archaeologists have unearthed a Roman catacomb and an ancient church dedicated to Saint Valentine. In 496 AD Pope Gelasius marked February 14th as a celebration in honor of his martyrdom. (Catholic Online)

In 1836, some relics that were exhumed from the catacombs of Saint Hippolytus on the Via Tiburtina, then near (rather than inside) Rome, were identified with St. Valentine, placed in a casket, and transported to the Whitefriar Street Carmelite Church in Dublin, Ireland, to which they were donated by Pope Gregory XVI. Many tourists visit the saintly remains on St. Valentine's Day, when the casket is carried in solemn procession to the high altar for a special Mass dedicated to young people and all those in love.

I came across this church by accident in Dublin in 2009 - we just happened to be staying at a hostel across the street and were looking for a Mass: