(Just a quickie - Freddie Mercury definitely was in the forefront)
It was written by Freddie Mercury for the band's 1975 studio album
A Night at the Opera. It is a six-minute suite, consisting of several sections without a chorus: an intro, a ballad segment, an operatic passage, a hard rock part and a reflective coda. The song is a more accessible take on the 1970s progressive rock genre. It was the most expensive single ever made at the time of its release. It is one of Queen's most popular songs and is frequently placed on modern lists of the greatest songs of all time. The single was accompanied by a promotional video (I listed above), which many scholars consider ground-breaking.
Rolling Stone magazine states: "Its influence cannot be overstated, practically inventing the music video seven years before MTV went on the air."