Rainbow headlined the first Monsters of Rock festival at Donington Park in 1980.
The festival took place on 16 August 1980 at the Donington Park motor-racing circuit in Leicestershire, England. Rainbow topped a bill that also included Judas Priest, Scorpions, Saxon, April Wine and Touch. The event attracted roughly 35,000 people and became one of the most important recurring festivals in hard rock and heavy metal.
Monsters of Rock returned annually at Donington for much of the 1980s and 1990s. Its stage hosted many major metal acts, including Iron Maiden, Metallica, AC/DC and Black Sabbath. Because the festival was strongly associated with Donington, later large rock events at the site are sometimes casually grouped with it, although they were separate festivals.
Rainbow was formed by former Deep Purple guitarist Ritchie Blackmore. Its 1980 lineup featured vocalist Graham Bonnet, but Bonnet left the band later that year.