In the 9th century the "Palatinate Franconofurd developed" into one of the political centres of the eastern Franconian empire. Around the year 1000, the old town area was fortified under the Ottonian dynasty with a wider wall ring. It is unclear whether the core settlement had already expanded beyond the Carolingian wall at this time. Recent publications cautiously point out that at the earliest from the middle of the 10th century there was a very long transition from the post house to the half-timbered building with stone foundations, the scanty findings actually point to a slow expansion of the city limits at that time.