Many prominent progressive rock bands got their initial exposure at large rock festivals that were held in Britain during the late 1960s and early 1970s. King Crimson made their first major appearance at the 1969 Hyde Park free concert, before a crowd estimated to be as large as 650,000, in support of the Rolling Stones. Emerson, Lake &amp; Palmer debuted at the 1970 Isle of Wight Festival, at which Supertramp, Family and Jethro Tull also appeared. Jethro Tull were also present at the 1969 Newport Jazz Festival, the first year in which that festival invited rock bands to perform. Hawkwind appeared at many British festivals throughout the 1970s, although they sometimes showed up uninvited, set up a stage on the periphery of the event, and played for free.