Question: was rudolf one of santa's original reindeer

Answer: No, In traditional lore, Santa Claus's sleigh is led by eight reindeer: Dasher, Dancer, Prancer, Vixen, Comet, Cupid, Dunder (variously spelled Donder and Donner) and Blixem (variously spelled Blixen and Blitzen), with Rudolph being a 20th-century inclusion.