During autumn and summer 1943 the Wehrmacht suffered heavy losses in men and materiel at the hands of the Red Army on the Eastern Front. At the same time, it had to conduct a build-up of military strength in France, prior to the expected invasion, and to reinforce the Italian theatre, where the Allies had crossed the Straits of Messina and landed on the Italian mainland at Salerno, and Termoli in September 1943. The Ersatzheer could therefore no longer generate the replacements to bring up to strength formations that had been depleted in battle in the east.