All the way down to Rome, occasionally. But please don't call the thing today's northern Italy was part of "Germany". That empire was an administrative framewor

All the way down to Rome, occasionally. But please don't call the thing today's northern Italy was part of "Germany". That empire was an administrative framework for nomadic kings that had little to do with today's concepts of nation or ethnicity. If you can't do without mapping to current states, you have to pick Austria, because Vienna is where the Habsburg emperors had their main residence.