Although he was never Emperor , Henry I the Fowler , Duke of Saxony , was the founder of this imperial dynasty , since his election as German king made it possible for his son , Otto the Great to take on the imperium . Although never Emperor , Henry I the Fowler , Duke of Saxony , was arguably the founder of this imperial dynasty , since his election as German king made it possible for his son , Otto the Great to take on the imperium .