Waterloo

There are two bands and a singer with this name and also an ABBA tribute band:

1) Waterloo was a proto-prog outfit from Ghent, Belgium, active from 1969 to 1972. They recorded an album, "First Battle", in London in late 1969, produced by David MacKay and released on the French label Vogue in February 1970. Stylistically, the album is heavily influenced by "Stand Up"-era Jethro Tull and keyboard-based British prog bands of that era, such as Arzachel.