Them were a Northern Irish band formed in Belfast in April 1964, most prominently known for the garage rock standard “Gloria” and launching singer Van Morrison’s musical career. Wikipedia
Them’s history is more confused than that of any other significant British Invasion group. In his The Beatles and Some Other Guys: Rock Family Trees of the Early Sixties, Pete Frame documents no less than nine lineups of the group between 1964 and 1966. His extensive Them family tree does not take into account several occasions in which original members Eric Wrixon and Billy Harrison rejoined the band briefly. And let’s not even talk about the post-Van Morrison version of Them, which managed to make four albums in America–twice as many as Them had been able to put out while Morrison was in the group. On top of all this, confusion persists to this day whether session men played a large role in their recordings. About the only thing certain is that Van was the only one singing lead on the pre-1967 discs. This has made it difficult to give the group a solid identity, other than that of an amorphous Van Morrison backup unit, to historians.
Them forged their hard-nosed R&B sound in Belfast, Northern Ireland, moving to England in 1964 after landing a deal with Decca Records. The band’s simmering sound was dominated by boiling organ riffs, lean guitars, and the tough vocals of lead singer Van Morrison, whose recordings with Them rank among the very best performances of the British Invasion. Morrison also wrote top-notch original material for the outfit, whose lineup changed numerous times over the course of their brief existence. As a hit-making act, their résumé was brief — “Here Comes the Night” and “Baby Please Don’t Go” were Top Ten hits in England, “Mystic Eyes” and “Here Comes the Night” made the Top 40 in the U.S. — but their influence was considerable, reaching bands like the Doors, whom Them played with during a residency in Los Angeles just before Van Morrison quit the band in 1966. Their most influential song of all, the classic three-chord stormer “Gloria,” was actually a B-side, although the Shadows of Knight had a hit in the U.S. with a faithful, tamer cover version.
Morrison recalled his days with Them with some bitterness, noting that the heart of the original group was torn out by image-conscious record company politics, and that sessionmen (including Jimmy Page) often played on recordings. In addition to hits, Them released a couple of fine albums and several flop singles that mixed Morrison compositions with R&B and soul covers, as well as a few songs written for them by producers like Bert Berns (who penned “Here Comes the Night”). After Morrison left the group, Them splintered into the Belfast Gypsies, who released an album that (except for the vocals) approximated Them’s early records, and a psychedelic outfit that kept the name Them, releasing four LPs with little resemblance to the tough sounds of their mid-’60s heyday.
Extracts from http://www.allmusic.com/artist/them-mn0000925181