Those Who Are About to Die Salute You - Morituri Te Salutant is the debut album by Colosseum, released in 1969 by Fontana. It is one of the pioneering albums of jazz fusion. The title is a translation of the Latin phrase morituri te salutant that according to popular belief (but not academic agreement), gladiators addressed to the emperor before the beginning of a gladiatorial match.
"Debut" is the very first song Colosseum ever played as a group. Tony Reeves later recalled that "["Debut"] was actually a phrase that I remembered Mick Taylor playing with John Mayall, and I changed it a bit into a bass line. [Sings the part.] And then the band all joined in - this is what happens during rehearsals - so technically you should have everybody's name in the writing credit, including, I guess, Mick Taylor's!" 
"Mandarin" started from a series of sketches by Dave Greenslade based on a Japanese soft scale. Tony Reeves compiled the sketches into the main theme and arranged the song.
Allmusic's review was laudatory, saying the album "is a powerful one, unleashing each member's instrumental prowess at one point while consolidating each talent to form an explosive outpouring of progressive jazz/rock the next." They highly praised the variety and uniqueness of each song, the playing of the musicians, and the group's ability to create a blend of jazz, rock, and classical elements that was unconventional yet accessible. They concluded "the album never strays from its intensity or its creativity", and added that Valentyne Suite is similar and just as outstanding, even though Allmusic's official review of that album is largely negative.