Our father among the saints Nicholas of Myra, Wonder-worker, was the archbishop of Myra in southern Asia Minor in the fourth century and is also the basis for the Santa Claus legends and imagery which accompany Christmas celebrations in much of the world.

In addition to being honored as the patron saint of many countries, notably Greece and Russia, and of cities, he is the patron of many occupational groups, most notably of sea-farers.  St. Nicholas is commemorated by the Church on December 6, and also on May 9 (the transfer of his relics) and on July 29 (his nativity).

Source:  www.orthodoxwiki.org