Santa Claus has evolved over centuries from multiple influences and folk traditions. Early depictions of Santa were influenced by poems and illustrations in the 1820s, showing him arriving by sleigh pulled by reindeer. These were based on traditions of figures like the 4th century St. Nicholas and Norse gods like Odin and Thor. Over time, Santa absorbed elements from pagan winter solstice celebrations and nature spirits. While modern Santa is typically seen as a cheerful gift-giver, his origins involve more complex and sometimes frightening pagan influences that have been incorporated into Christmas traditions.