"Holy roman empire of german nation" is the closest possible translation,
but the time when Italy was part of it was very limited, (14th century) and it
wasn't even really part of it, just that the german Kaiser was also the italian King ....
And back than about 1/3 of Italy was the Vatikan-state.
The Reich had really no more meaning and power in those days than the
UN has today, and the unity it had in it's beginning (9th century) was long
lost. Ever wondered why the national anthem speaks so much about "unity"
when it was written in the mid 19th century ?