Saint Nicolas of Myra was absolutely a real person who was famous for secret gift-giving.
His legacy created the idea of Santa Claus around the world. Millions - possibly billions of people around the world get presents from Santa Claus (or Sinterklaas, etc.) every year.
If you accept Santa Claus as a deeply-rooted part of western folklore, then not only did he exist in the 4th century, but he exists today just as surely.
Santa is real. He just hates poor people because he's 3 capitalists in a trenchcoat. Which isn't even that much of a disguise considering he uses slave labor to make all his toys.