Designed to be relatively lightweight and simple, the Fox platform was initially developed to replace several derivatives of the Ford Falcon compact architecture dating from 1960. For 1978, the Ford Fairmont and Mercury Zephyr were the first models derived from the chassis, replacing the Ford Maverick and Mercury Comet. As downsizing expanded into the intermediate segment, the Fox platform came into use for mid-size applications, replacing the larger Ford Torino chassis. While best known for underpinning the Ford Mustang pony car, the Fox platform also saw use in personal luxury segments, underpinning coupes for all three Ford divisions.