Ruja was one of the foremost Estonian rock bands of the 1970s and 1980s. The band was influenced by Western acts such as Genesis, Yes, Emerson Lake and Palmer and King Crimson, and often incorporated the poetry of Estonian writers Juhan Viiding and Ott Arder into their lyrics. The band and its music went through many changes which are known as the four periods of Ruja: the early period (1971-1975), the progressive period (1976-1979), the pop period (1981-1984) and the late period (1985-1988). The core members of the group were Rein Rannap (keyboard, melody), Urmas Alender (vocals), Jaanus Nõgisto (guitar) and Andrus Vaht (drums). Other members of the band have at different times included Andres Põldroo, Tiit Haagma, Raul Sepper, Toomas Veenre, Paul Mägi, Heiki Kalaus, Indrek Avasalu, Heiki Tark, Liina Randmaa, Eva Ojaveer, Margus Kappel, Ivo Varts, Priit Kuulberg, Jaan Karp, Igor Garshnek, Toomas Rull, Arvo Urb, Vladislav Petshnikov as S. P. Gulliver, Nevil Blumberg, Rein Joasoo. After vocalist Urmas Alender died in the 1994 sinking of passenger ferry M/S Estonia, the remaining members of the band decided never to perform under the name Ruja again. Nevertheless, their songs remain popular through their recordings, cover versions and the occasional performance by the group's chief songwriter Rein Rannap.