In the first half or the 4th century he was Bishop of Myra, roughly 100 km southwest of Antalya in Turkey.
His commemoration day is on December 6th, which is linked to many different customs. In some countries, he appears in the evening and brings presents to the children, who have been good.
Depending on the legend, he has different companions, e.g. Servant Rupert (Knecht Ruprecht) as mentioned in the poem of Theodor Storm (PI-Advent Calendar #4).
In some countries, e.g. Luxembourg usually the presents are received on December 6th, rather than at Christmas.
Wishing a wonderful Saint Nicholas day to all the children and adults around the world!