Complex sentence: In 1947, at the eve of the Cold War, he created the Mexican DFS intelligence agency, to support and cooperate with CIA operations in Mexico, it'st stated mission was "preserving the internal stability... against all forms subversion".
Split into simpler sentences: In 1947, on the eve of the Cold War, he created the Mexican DFS intelligence agency to support and cooperate with CIA operations in Mexico. Its stated mission was "preserving the internal stability... against all forms of subversion".