Nevertheless, by 1866, the imminence of Maximilian's abdication seemed apparent to almost everyone outside Mexico. That year, Napoleon III withdrew his troops in the face of Mexican resistance and U.S. opposition under the Monroe Doctrine, as well as to strengthen his forces at home to face the ever-growing Prussian military and Bismarck. Carlota travelled to Europe, seeking assistance for her husband's regime in Paris and Vienna and, finally, in Rome from Pope Pius IX. Her efforts failed, and she suffered a deep emotional collapse and never went back to Mexico.