Them was formed in Belfast in 1963, the original line-up being Billy Harrison (guitar), Eric Wrickson (organ), Alan Henderson (bass), Van Morrison (vocals/harmonica) and Ronnie Millings (drums). Morrison had previously played in a showband called The Monarchs.  In July 1964 Wrickson departed to join The Wheels and Millings also left to become a milkman. Decca's Dick Rowe, having seen them perform at the Maritime, arranged a recording audition in London and to find a debut single. Seven songs were recorded, Groovin', You Can't Judge A Book, Turn On Your Lovelight, Gloria, One Two Brown Eyes, Philosophy and Don't Start Crying Now.

The last number was chosen for their first 45. It failed to break through nationally but sold well in Belfast.  For their second single they covered the American blues classic, Baby Please Don't Go. With the stunning garage-punk standard, Gloria, on the B-side, this was arguably one of the finest R&B singles of the sixties. Both tracks featured fine vocal performances from Morrison but the remaining band members contributed little with Rowe utilising experienced sessionmen like Jimmy Page, who was responsible for the single's fine guitar moments. In Great Britain, Baby Please Don't Go made the Top Ten.

American producer Bert Berns (whose earlier credits included Hang On Sloopy, Twist And Shout and Under The Boardwalk) wrote and produced their next single, Here Comes The Night, which had been recorded by Lulu the previous year without much commercial success. This near-ballad featured another stunning vocal performance by Morrison and rose to No 2, becoming their biggest but last British hit. In April 1965 the first in a series of line-up changes took place, which culminated in the death of the band. Jackie McAuley left, totally disillusioned by the continual involvement of session-men on the band's recordings. He was replaced by Pete Bardens.

In July 1965, Jackie's brother Pat left (to be replaced by Terry Noone) and Billy Harrison was replaced by Joe Boni. In September 1965, Morrison and Henderson sacked Bardens, Boni and Noon and headed back to Belfast to look for new personnel. The McAuley brothers then formed Belfast Gypsies.  A debut album, Them (sometimes referred to as Angry Young Them because that description appears on the back cover), came out in June 1965.  In September 1965 Morrison and Henderson returned with another new line-up which is credited with recording the Them Again album, which mixed R&B standards with some Morrison originals.

However, the album was apparently made with the assistance of other session players. Them finally split in June 1966 but later re-grouped in Los Angeles with Belfast vocalist Kenny McDowell (Moses K of The Prophets) in Morrison's place. This line-up cut two albums on Tower and continued, based in the US, into the seventies. The Now And Them album was a curious mixture of blues-rock and psychedelia.  Prior to the follow-up Roy Elliot departed and the band became a quartet. By the time of their second Tower album, Them were a fully fledged psychedelic rock band. Sadly, it marked the end of this line-up who split in 1968, disillusioned by their financial situation. Armstrong and McDowell formed Sk'boo back in Belfast.