Three saints named Valentine are traditionally associated with martyrdom on February 14.
The tradition comes from hagiographical sources that mention a Roman priest, Valentine of Interamna (modern Terni), and a third Valentine said to have suffered martyrdom with companions in the Roman province of Africa. The first two were both linked with the Via Flaminia outside Rome, which helped create confusion between their stories.
These accounts are late and contain legendary elements, so some historians think the Roman priest and the bishop of Terni may represent the same historical person. The modern Roman Martyrology lists only one Valentine for February 14, a martyr associated with the Via Flaminia. Nevertheless, “three” is the conventional answer when the question refers to the traditional hagiographical identifications.
Saint Valentine’s feast became associated with romantic love much later, especially during the High Middle Ages. The martyr traditions themselves are older than the romantic customs.