This Amsterdam pop group was already popular on the local scene for years before they got nationally famous with the hit Hair from the musical of the same title.

The band was formed in 1965 by Siebe de Jong (v, s, fl, b); various other members came and went: Caro Kalkman (v), Dirk Van Der Ploeg (v, g, later solo), Valentijn Geverts (dr, o, p, in 1968 replaced by Wim Taarling, ex-Trix & Paramounts), Bart Bos (b) and Duco De Rijk (v, g, member from 1967 'til 1970, ex-Graaf X & Klimax, in 1970 to Gallery). In 1968, John Brands (ex-Elements, to Playboys and solo) joined as a singer. Supported by Radio Veronica, the band slowly garnered national recognition. In fact, they ended up topping the 1968 Hitweek hit parade chart! After the split of the Ro-d-ys from Groningen in 1969, the latter group merged together with Zen, resulting in the following line-up: Siebe, Bart, Wim, Bennie Groen (d, ex-Ro-d-ys) and Harry Rijnbergen (v, g, ex-Ro-d-ys, to Harley Jay), and 2 singles.

In 1970, Zen broke up. Three years later, Siebe came up with a new line-up for his group: Dave Vreeland (v, s, o, p), Ruud Klokgieter (v, g), Eddy Postema (b, g, to Stud), Johan van der Meer (v, b) and Floris van Manen (dr, later in Bots). In 1973 they recorded the album ‘Again’. Eddy was replaced by Peter Huying in 1974. This line-up existed 'til 1975. In the same year the band featured: Siebe de Jong (v, s, fl), Tony Souren (v), Peter Huying (g), Dick Hendriks (dr, in 1975 replaced by Peter Swinkels who later went to Attraction), Ruud Klokgieter (v, g) and (for a short while) Alex de Laar (v). Come 1977, the new Zen included: Ar Jelier (o, p, v, to Intercity), Frank Tijdink (g, to Intercity), Dick Tolsma (to Joe Monroe Band), Siebe de Jong and Cor Kerker.