In 1965, the Federal Communications Commission ordered AM stations in large markets to end continuous simulcasting on co-owned FM frequencies, a move made to spark development of FM stations as individual entities. On July 30, 1966, WOR-FM began running a freeform-based progressive rock format for most of its broadcast day, though the station continued to simulcast WOR radio's morning program "Rambling with Gambling" for a time afterwards. Under the leadership of legendary disc jockey Murray "the K" Kaufman, and featuring other notable disc jockeys such as Scott Muni and Rosko, the freeform format was the first of its kind in New York City radio. At that point, Muni and Rosko departed for WNEW-FM, where the progressive format would become a huge success.