Saint Valentine was a Roman who was killed for his faith on February 14, 269 A.D. He had refused to worship pagan gods, and some stories say he was a priest who would marry young couples in secret who loved each other but who did not have parental permission. In 496, his 'saint day' was established. He is associated with love because he fell in love with the daughter of his jailer, and would pass notes to her. His final note, before he was executed, read 'from your Valentine'.
Over the centuries, February 14th has become firmly associated with love, romance and sweethearts in every country around the world. There are many traditions involved with Valentine's Day. In most countries it is a traditional day to become engaged. In Italy, it's a day when men and women listen to music together and share poetry. In Victorian England, elaborate Valentine's Day cards were shared with family and friends. In Germany, flowers were definitely expected!
The key to a tradition is that it comes from the heart. Valentine's Day is NOT about expensive jewelry or $100 bouquets of hot-house roses. It is about showing someone you really care, and that you have made or found a present for them that only your intimate knowledge of their personality could have known about. It's about that connection between two people, a connection that money can't buy.