The Holy Roman Empire was, in many ways, a unified Germany (albeit a very loosely unified one).

Here is a map of the empire around 1800.

Also worth listening to: the HRE national anthem - Gott Erhalte Franz den Kaiser - which was composed by Haydn in 1794 for Franz II Holy Roman Emperor (who dissolved the empire after the battle of Austerlitz and created the new Austrian Empire as Franz I). The melody has been used both as a family hymn by the Habsburgs ever since, and is today the German national anthem. Here it is being sung at Otto von Habsburg's funeral in Vienna a couple of years ago.