I can't recall when I determined to transcribe "The Planets" for clarinet choir, but it was surely encouraged by the tremendous excitement (and size) of the UIUC Clarinet Choir in the 2017-2018 academic year. With over thirty members in the spring, putting on such a large-scale performance seemed, if not straightforward, at least feasible. So, never one to shy from large-scale projects, it simply had to happen at some point.
Holst composed the seven-movement suite between 1914 and 1916. While each movement is named after a planet, Holst based the character of each movement on the astrological character associated with the planet rather the Roman deities or the celestial bodies themselves. Because of its large-scale nature and novel orchestration, the suite enjoyed tremendous popular success, much to Holst's bemoaning the neglect of his other works.