Excerpts from Books and Wikipedia
"Before this happened, Louis expected William's expedition to England to absorb his energies and those of his allies, so he dispatched troops to the Rhineland after the expiry of his ultimatum to the German princes requiring confirmation of the Truce of Ratisbon and acceptance of his demands about the succession crises. This military manoeuvre was also intended to protect his eastern provinces from Imperial invasion by depriving the enemy army of sustenance, thus explaining the preemptive scorched earth policy pursued in much of southwestern Germany (the "Devastation of the Palatinate"). [Wikipedia] "This ghastly process is usually referred to as ‘the devastation of the Palatinate’, but in fact it embraced a much more extensive swathe of German territory on both the left and the right banks of the Rhine. About twenty substantial towns were destroyed, including Bingen, Oppenheim, Worms and Speyer, and untold numbers of villages. . . . They then advertised their achievement by striking a medal bearing the motto ‘Heidelberga deleta’ (Heidelberg obliterated) . . ." [Blanning: Pursuit of Glory, p. 546-7]