What Did He DO?
Alvaro Obregon was a simple farmer that joined the war near the end. He rounded up men to join the General Agustine Sangines. Obregon defeated an army of orozquistas at the battle of San Joaquin. The general was later wounded in Chihuahua and fled. Obregon went back to tending his farm. He then rounded up his men again and they captured villages from the federal soldiers in Sonora. Obregon allienced with Carranza after he welcomed him.
When And Where and Why?
During 1914 in the city of Sonora. All of the other "Big Four": Pancho Villa, Emiliano Zapata, and Venustiano Carranza. Obregon was able to defeat them all once he was allied with Carranza.
How Did It make Changes?
Alvaro Obregon won many battles with Carranza. Once the War was over Obregon campaigned to be president and was suppose to get support by Carranza according to the arrangement's he made with Carranza.
How did this change the fate of Mexico?
Obregon did get support from others and was elected president. It was said that him being president put an end to the War. He was assasinated later by someone that was sent by Carranza. He was said to be one of the "Big Four" that actually survived longer than the others.