CIRCA: is a progressive rock supergroup founded by four musicians associated with Yes: current Yes member Alan White (drums), former Yes members Tony Kaye (Hammond, keyboards) and Billy Sherwood (bass, vocals), and guitarist Jimmy Haun, who played on the Yes album Union. Jimmy Haun and Michael Sherwood (Billy's elder brother) were childhood friends and went on to form the band Lodgic, which Billy joined in 1981. A few years after Lodgic split up, Billy Sherwood was introduced to Yes bassist Chris Squire and other members of Yes, including Kaye and White. Sherwood worked with the band on material for their next album. Meanwhile, both Haun and M. Sherwood came to do session work on an album from rival Yes faction, Anderson Bruford Wakeman Howe. Following a reconciliation between the Yes camps, material from both projects was combined for the 1991 album Union, which thus features B. Sherwood on the track "The More We Live—Let Go" and Haun and M. Sherwood on further tracks. Squire and B. Sherwood had written a body of material not used on Union; subsequently, they briefly toured this under the name of The Chris Squire Experiment in 1992, with a line-up including White and Haun. (The Chris Squire Experiment later evolved into Conspiracy.) Billy Sherwood continued an on/off association with Yes over the next few years, joining the live line-up for the Talk tour in 1994, with Jon Anderson, Trevor Rabin, Chris Squire, Alan White, and Tony Kaye. After this, in 1995, Sherwood and Rabin did some writing together, and two tracks on the CIRCA: 2007 album are based on this material. Billy Sherwood eventually joined Yes for a few years before leaving again. In the mid-2000s, he organised two Pink Floyd tribute albums, Back Against The Wall and Return To The Dark Side Of The Moon, and some further projects which featured an array of former and current Yes members as guests, including Kaye, White, Geoff Downes, Peter Banks, Bill Bruford, Steve Howe, and Rick Wakeman. Coming out of the second of these projects, Sherwood suggested to Kaye that they put together a project using former and current members of Yes. Going under a working title of Family or Family Project, various names were floated, and White and Banks (and perhaps others) were approached. However, in 2006, as the project developed, Sherwood and Kaye decided to change tack and focus on creating a unitary band. They recruited Alan White on drums and Jimmy Haun on guitar and recorded their debut album. CIRCA: was formally announced in March 2007.
- Billy Sherwood - Lead Vocals, Bass
- Tony Kaye - Hammond Organ, Keyboards
- Alan White - Drums, Percussion, Vocals
- Jimmy Haun - Electric Guitar, Acoustic Guitar, Vocals