Is it ensure, insure, or assure?
music written for performance in a religious rite of worship; the term is most commonly associated with the Christian tradition. Developing from the musical practices of the Jewish synagogues, which allowed the cantor an improvised charismatic song, early Christian services contained a simple refrain, or responsorial, sung by the congregation. This evolved into the various Western chants, the last of which, the Gregorian, reached its apogee in the Carolingian Renaissance. From the 10th century there also emerged a vast number of hymns.