How did the remains of St Valentine end up in a Dublin church?

The faithful come from far and wide to pray in the Carmelite Whitefriar Street Church. In the 18th century building, an alarmed casket contains a number of St Valentine's bones and a vial of his blood. A small inscription on the box reads: 'This shrine contains the sacred body of Saint Valentinus the Martyr, together with a small vessel tinged with his blood.'

The relics have been in the Dublin church since 1836, when Dublin preacher Fr. John Spratt was gifted them by Pope Gregory XVI.