In the late 1960s, 4 guys in the UK came up with the bright idea of a group which would feature twin lead guitars, harmonised or otherwise similarly complementary.
This is therefore a rare example of a group whose name is descriptive of itself.
The first, eponymous, album came out in 1970, and is another classic, blissful LP, as are the next two, “Pilgrimage” and “Argus”, both from 1972. Many view “Argus” as their best ever, and indeed one of the greatest albums in history, and I sympathise with this view. However, my favourite remains the first one.
Sadly, after 1972 and “Argus”, the magic went. They never really got the twin guitar style back, and became just another competent rock band.
They thus have this syndrome in common with, e.g. Cat Stevens.