The Holy Roman emperor Otto I (912-973), called Otto the Great, was the most powerful western European ruler after Charlemagne. He organized a strong German state and expanded his authority over Burgundy and Italy.

Otto I was the son of King Henry I (the Fowler) of Germany. In 929 he married Edith, daughter of Edward the Elder of England; she died in 946. Otto was Duke of Saxony when his father died in 936, and he was at once elected king (which rule he held until 962) at Aix-la-Chapelle by the great magnates. The rulers of the other great duchies caused Otto initial problems. By 947 he had solved them by absorbing the duchy of Franconia into his direct rule and by handing over the others, Lorraine, Swabia, and Bavaria, to members of his family.

By 951 Otto had been drawn into Italy by the fear that its widowed Queen Adelaide, who was having...