The primary cause of the Mexican Revolution was the policies of the administration of Porfirio Díaz. The Díaz administration mistreated the poor and rural workers and implemented unpopular land laws that ceded the land of small farmers to wealthy foreigners.
Díaz first took power in 1876 by ousting Sebastián Lerdo de Tejada. He quickly implemented a policy disallowing presidents from serving successive terms but governed by proxy, using successor Manuel González Flores until he was again eligible to run. In his second term as president, he abandoned the policy and used a series of fraudulent elections to stay in power until 1911.
Although Díaz industrialized the country and modernized its infrastructure, he often did so by unpopular and sometimes brutal methods. He kept a personal police force called the rurales to intimidate citizens into voting for him and accepting his policies. He also suppressed the media and created massive income and land inequality, resulting in a large, permanent class of landless laborers. These laborers were typically abused.
Several independent rebellions, including rebellions led by Pancho Villa and Francisco I. Madero, eventually came together as the Mexican Revolution. Díaz was pressured into stepping down in 1910, and he was succeeded as president by Madero, marking the formal beginning of the armed Mexican Revolution.