At that time, in Hermosillo, capital of Sonora, there were five hundred men under the command of Lieutenant Colonel Obregon, who later in the campaign became a famous general under Carranza. Major Salvador Alvarado, now general, had command of four hundred troops of the Yaqui region, while in the southern part of the State, five hundred men were under the command of Generals Juan Cabral, Benjamin Hill and Sosa. Many of the officers and soldiers of this army had participated in the revolution of 1910, consequently they were opposed to the dictatorship of Huerta. This marked the beginning of the Sonora revolution. Even before the assassination of Madero, there were a number of chiefs who waged a relentless war. They were Col. Pedro F. Bracamonte, Col. Plutarco Elias Calles, and Major Campos. They began to recruit people on their own authority in the northern part of the State, and the cutting of railway communication. They also began an open attack on the Federals in many places. When the Sonora revolution was started, the chiefs became united, and opened hostilities. At the beginning of the Sonora revolution, the Federals had a force of 2,650 troops distributed throughout the State, from the frontier to the coast. Bearing this in mind, the Constitutionalists mapped out a careful campaign. General Obregon was appointed to direct the military operations, as he had distinguished himself in the campaign of 1912 against the Orozquistas. The difficult task that the Constitutionalists were confronted with, was the prevention of the concentration and the union of the entire Federal army. They knew that as long as the Federal army was divided and spread throughout the State, their chances were more than equal. Thus they had a double task: first, to prevent the union of the Federal troops, and secondly to fight them in small groups. The main object of the Constitutionalists was to secure the border positions of the State. As the revolution progressed and the fighting continued, the Constitutionalists found their plans perfectly suited to their needs. They marched from one city to the next, sometimes under terrible difficulties, but always victorious. All those in command, and also the troops, fulfilled their duties admirably. Soon, however, they were confronted with new and unexpected troubles.