A physician and priest living in Rome during the rule of the Emperor Claudius, Valentine become one of the noted martyrs of the third century. The commemoration of his death, which occurred in the year 270, became part of the calendar of remembrance in the early church of the West. Tradition suggests that on the day of his execution for his Christian faith, he left a note of encouragement for a child of his jailer written on an irregularly-shaped piece of paper. This greeting became a pattern for millions of written expressions of love and caring that now are the highlight of Valentine’s Day in many nations.
Source: www.LCMS.org Commemorations Biographies