He continued to enjoy the favour of the king and was promoted to the rank of general of the infantry (1869), but the bitterness of his disappointment of 1866 never left him. He was grey-haired at forty-two, and his health was impaired. In 1869 von der Tann-Rathsamhausen, as he was now called, was appointed commander of the I. Bavarian Corps. This corps he commanded during the Franco-Prussian War of 1870/71, and it was in this war that he secured his reputation as one of the foremost of German soldiers. His gallantry was conspicuous at the battles of Wörth and Sedan. Transferred in the autumn to an independent command on the Loire, he conducted the operations against d'Aurelle de Paladines, at first with marked success, and forced the surrender of Orléans. He had, however, at Coulmiers to give way before a numerically larger French force; but reinforced, he fought several successful engagements under the Grand Duke of Mecklenburg-Schwerin near Orléans.