The frontier which they form is inconveniently long, enclosing an acute-angled wedge of foreign territory - the modern Baden and Wurttemberg.
The first advance came about 74, when what is now Baden was invaded and in part annexed and a road carried from the Roman base on the upper Rhine, Strassburg, to the Danube just above Ulm.
In the spring of 1848 he was in Germany, and on the outbreak of the revolutionary troubles he accepted the invitation of the government of Baden to take the command against the insurgent "free companies" (Freischaaren).
For the Rhine provinces not incorporated in Prussia, with the special object of regulating episcopal elections; concerned Wurttemberg, Baden, Hesse, Saxony, Nassau, Frankfort, the Hanseatic towns, Oldenburg and Waldeck.
It had to be replaced by new concordats concluded with Wurttemberg in 1857 and the grand-duchy of Baden in 1859; but these conventions, not having been ratified by those countries, never came into force.
