Complex sentence: Colosseum's second album, also in 1969, was "Valentyne Suite", notable as the first release from Vertigo Records, the first label to sign heavy metal pioneers Black Sabbath.
Split into simpler sentences: Colosseum's second album, their second release in 1969, was "Valentyne Suite". It is well-known as the first album release from the label Vertigo Records, which also first signed heavy metal pioneers Black Sabbath.