According to The Golden Legend (1260):
S. Valentine, friend of our Lord and priest of great authority, was at Rome. It happed that Claudius the emperor made him to come to fore him and said to him in demanding: What thing is that which I have heard of thee, Valentine? Why wilt thou not abide in our amity, and worship the idols and renounce the vain opinion of thy creance? S. Valentine answered him: If thou hadst very knowledge of the grace of Jesu Christ thou shouldest not say this that thou sayest, but shouldest reny the idols and worship very God. Then said to S. Valentine a prince which was of the council of the emperor: What wilt thou say of our gods and of their holy life? And S. Valentine answered: I say none other thing of them but that they were men mortal and mechant and full of all ordure and evil. Then said Claudius the emperor: If Jesu Christ be God verily, wherefore sayst thou not the truth? And S. Valentine said: Certainly Jesu Christ is only very God, and if thou believe in him, verily thy soul shall be saved, thy realm shall multiply, and he shall give to thee alway victory of thine enemies. Then Claudius turned him unto all them that were there, and said to them: Lords, Romans, hear ye how wisely and reasonably this man speaketh? Anon the provost of the city said: The emperor is deceived and betrayed, how may we leave that which we have holden and been accustomed to hold sith our infancy? With these words the emperor turned and changed his courage, and S. Valentine was delivered in the keeping of the provost.
When S. Valentine was brought in an house in prison, then he prayed to God, saying: Lord Jesu Christ very God, which art very light, enlumine this house in such wise that they that dwell therein may know thee to be very God. And the provost said: I marvel me that thou sayest that thy God is very light, and nevertheless, if he may make my daughter to hear and see, which long time hath been blind, I shall do all that thou commandest me, and shall believe in thy God. S. Valentine anon put him in prayers, and by his prayers the daughter of the provost received again her sight, and anon all they of the house were converted. After, the emperor did do smite off the head of S. Valentine, the year of our Lord two hundred and eighty. Then let us pray to S. Valentine that he get us pardon of our sins. Amen.
According to The Nuremberg Chronicles (1493):
Valentine (Valentinus), a Roman priest, after giving evidence of exceptional learning and writing, was imprisoned by the Emperor Claudius; and being asked his opinion concerning the pagan gods, said: Jupiter, Mercury, and the other gods were miserable human beings. Afterwards he enlightened the daughter of Asterius. He brought her and forty-nine persons of her household to the Christian faith. Finally, at the command of the emperor, he was severely beaten with clubs, and was beheaded on the 14th day of the month of February.
According to The Roman Martyrology (1583):
At Rome, on the Flaminian road, in the time of the emperor Claudius, the birthday of blessed Valentine, priest and martyr, who after having cured and instructed many persons, was beaten with clubs and beheaded.