Under the reign of the Ottonian rulers , the kingdom of the Eastern Franks finally became Germany as the duchies of Lorraine , Saxony , Franconia , Swabia , Thuringia and Bavaria joined in one empire . Under the reign of the Ottonian rulers , the kingdom of the Eastern Franks finally became Germany with the conclusion of the unification of the duchies of Lorraine , Saxony , Franconia , Swabia , Thuringia and Bavaria into one empire .