Saint Nicholas (270–6 December 346) is the canonical and most popular name for Nikolaos of Myra, a saint because of the many miracles attributed to his intercession, he is also known as Nikolaos the Wonderworker. He had a reputation for secret gift-giving, such as putting coins in the shoes of those who left them out for him, and thus became the model for Santa Claus, whose English name comes from the Dutch Sinterklaas.
Why do you think they call Santa Claus St. Nick? You might recognize him like this:
In Germany, Nikolaus is usually celebrated on a small scale. Many children put a boot called Nikolaus-Stiefel (Nikolaus boot) outside the front door on the night of 5 December to 6 December. St. Nicholas fills the boot with gifts and sweets, and at the same time checks up on the children to see if they were good, polite and helpful the last year. If they were not, they will have a tree branch in their boots instead. Sometimes a disguised Nikolaus also visits the children at school or in their homes and asks them if they have been good. I remember doing this when I was at the DoDs public school elementary school in Giessen, Germany. It was fun!