Emerson, Lake & Palmer, is one of the earliest and most famous progressive rock supergroups.
The three musicians came from past experiences with bands already established  in the rock music scene, Keith Emerson came from Nice, Greg Lake from King Crimson and Carl Palmer had been part of the Crazy World of Arthur Brown, and later of Atomic Rooster.
Their debut album (Emerson Lake & Palmer) was published in 1970, after a memorable performance at the Isle of Wight Festival, and immediately it puts emphasis on the technical ability of the three musicians about use of their instruments and the choice of a sound which is a perfect blend of rock and classical.