In the Middle Ages in Western Europe, St. Valentine grew up legends.
They talked about the secret weddings of couples in love. Emperor Claudius 2 forbade the soldiers to marry. Allegedly he thought that marriage distracts from the service. Valentine secretly crowned the willing and for this was sentenced to death.
In fact, it's legends are fiction. They are refuted very easily:
The Emperor Claudius 2 ruled Rome in the 3rd century. Then Christianity was not yet recognized as the official religion. Therefore, there could not have been any mass weddings of soldiers.
Christianity at that time was an outlandish sect. And the authorities were completely uninteresting, what they are doing there. If only they pay taxes and do not violate the laws. And it was always possible to marry in secret, in the end. Why would the emperor pay attention to the fun of a couple of sects?
Finally, in the third century, the rite of the Wedding itself did not exist.
My conclusion from this knowledge: People like beautiful fairy tales about love. Hence the wonderful legends of St. Valentine.