Otto I (912-973), also known as Otto the Great, was the oldest son of King Henry I and inherited the Duchy of Saxony as well as kingship of East Francia, now also increasingly known as Germany, when his father died in 936. He unified the various duchies into one single kingdom, ensuring more power remained in the king's hands rather than that of the aristocracy, placing members of his family into all the duchies to reduce the power of the dukes, who had previously been co-equals with the king.