An image of Santa Claus published by the New York Historical Society in 1810 shows him as the traditional, European St. Nicholas. Within ten years, he was portrayed on rooftops with reindeer and a sleigh.
This short video, a Pictorial History of Santa Claus (in two minutes or less) shows several rare, early images of Santa Claus which illustrate how several of the most recognizable features of Santa Claus took root very early, although representations of Santa continued to vary dramatically for several decades.
Santa Claus also proves himself to be above politics - appearing with Union Troops in 1863 and with General Robert E. Lee in a post-war children's book, General Lee and Santa Claus.
Link: A Pictorial History of Santa Claus (in two minutes or less)
(Look for my more detailed history of Santa Claus appearing soon)