Excellent site with the history, and chronology of Mexico's transistion.

...Mexico: From Empire to Revolution covers approximately sixty years. It begins in 1857 with the appointment of Benito Juárez as acting President of the Republic and the arrival of the French photographer Désiré Charnay from France. It ends with the final phases of the Revolution, the election of Álvaro Obregón as President in 1920 and the photographs of 1923 that record the bloody assassination of one of the leaders of the Revolution, Pancho Villa. This period represents one of the most dramatic and violent in Mexico’s history. In that short span of time the country experienced imperial intervention followed by conflict, rebellion and finally revolution.

There are, in a sense, two histories here, a history of Mexico and another of photography: two histories that interact and reflect upon one another. The photographs taken had a powerful influence over the course of events. Many represent photo opportunities for leaders, groups and movements to publicize themselves and their cause. Other images expose harsh realities of brutality and violence that for some are best forgotten, These images provide evidence of what had disappeared or would be otherwise lost in the folds and shadows of a larger history of a nation and countries at war....except from site.