St Nicholas, the First Santa Clause
In Ireland, he's Deaide na Nollaig, in France he is Pere Noel, in Italy he is Babbo Natale, his role is filled by the Yule Lads in Iceland. He is Santa Claus (AKA Father Christmas) and he started out as a bishop named Nicholas who was born in what is now Turkey. Nicholas was Bishop of Myra, an Ancient Greek and Roman town found within Turkey's borders. He performed many miracles and was known as Nicholas the Miracleworker. He signed the cross at a woman whose hand was withered and restored it. He also declared three men who were about to be executed after takign the sword from the executioner that they were free which led to the one who ordered for the execution to happen to confess.
Of course, he had to give Santie some inspiration and giving charity is what St Nicholas is known for. Inspired by his parents, St Nicholas was a very charitable person who saved 3 girls from being sold into slavery by giving three bags of gold over the course of 3 nights to the girls' home. He gave gifts annonymously to those in need as a charitable cause.
In the years since his time, kids write to Santa who took over from some French nuns who claimed the presents they were giving were from St Nicholas. The Dutch (who call him Sinter Klaas) helped give him and us his modern name and it was at the suggestion of Thomas Nast that he is seen wearing red. Clement Clake Moore was lucky enough to document a visit from him and that's how we know about the reindeer pulled sleigh.
St Nicholas' feast day is 6 December and on the day before, the Dutch would leave their shoes out for St Nick to put small gifts into as a nice surprise for Dutch children to wake up the next day.