Trouble followed trouble in the north, which, be it remembered, runs to a distance of over a thousand miles from Mexico City itself. But nothing very serious occurred, until suddenly, in the early weeks of 1911, President Taft mobilized a force of 20,000 American troops to watch the Mexican frontier. From that time events developed rapidly till the end of the Diaz regime in May. One thing became clear, that the revolution was rapidly making its way to victory, and that Diaz, prostrate with an agonizing disease, an abscess of the jaw, was in no condition to rally his disheartened followers in person. He saved his honor, as the phrase goes, by a declaration that he would not retire from office until peace was declared, and he kept his word. He was too ill to leave his simple home in one of the chief streets of the city, where he lived less ostentatiously than many of his fellow citizens, but this did not prevent the mob from firing upon his home. On the afternoon of May 25, 1911, he resigned, and Señor De La Barra, formerly Minister at Washington, became provisional President until the next election, fixed for October. Madero was the hero of the hour. He entered Mexico City in triumphal procession, June 7, 1911. His entrance was preceded by the most severe earthquake the capital had known in years. Many buildings were wrecked and some hundreds of people killed. An arch of the National Palace fell, one beneath which Diaz had often passed. Three days after signing his abdication, General Diaz was well enough to leave Mexico City. In the early hours of the morning three trains drew up filled with his own solders and friends, in the middle one of which the ex-President, his wife, the clever and beautiful Carmelita, Colonel Porfirio Diaz, his son, with his young wife, several children, and their ten-days-old baby, were seated. Along the route the train came upon a force of seven hundred rebels. A sharp encounter ensued. The revolutionists left thirty dead upon the field; the escort, which numbered but three hundred, lost only three men. The old fighting spirit returned to the old lion, and, unarmed, the ex-President descended from his car and took part in the engagement. He entered Mexico City fighting, and he has left her shores with bullets ringing in the air. This was but the second time that Diaz had left the land of his birth.