To get rid of the problem, Claudius banned all marriages and engagements in Rome. Valentine, realizing the injustice of the decree, defied Claudius and continued to perform marriages for young lovers in secret.
When Valentine's actions were discovered, Claudius ordered that he be put to death. Valentine was arrested and dragged before the Prefect of Rome, who condemned him to be beaten to death with clubs and to have his head cut off. The sentence was carried out on February 14, on or about the year 270.
Legend also has it that while in jail, St. Valentine left a farewell note for the jailer's daughter, who had become his friend, and signed it "From Your Valentine." [history.com]
"Now you know..."