Complex sentence: The Raza Unida Party was established on January 17,1970 in Crystal City, Texas by José Ángel Gutiérrez and Mario Compean, who had also helped in the foundation of the Mexican American Youth Organization (MAYO) in 1967.
Split into simpler sentences: The Raza Unida Party was established on January 17th, 1970 in Crystal City, Texas. The two principle organizers were José Ángel Gutiérrez and Mario Compean who had also founded the Mexican American Youth Organization (MAYO) in 1967.