anniversary of the burial and on the third, seventh and thirtieth days following the death (Pruett, p. 751). Though only people of wealth and consequence could afford to have such a mass sung, the number of possible occasions on which it could be heard made this particular liturgical text very attractive to composers who, naturally enough, wanted to have their work heard often.
In the thirteenth and fourteenth centuries the requiem was so popular that numerous variations flourished. In its desire to achieve uniformity in its services, the church began to prohibit the celebration of requiems and other votive masses. The practice did not die out, however, and the form the requiem mass achieved by the late fourteenth century was adopted as the universal standard by the Council of Trent in 1543-1563 (Pruett, p. 751).
The masses were originally chanted in plainsong. Then polyphonic settings of the requiem mass began to be written in the late fifteenth century. But the practice was not encouraged by the church as it tended to lengthen services and, in many cases, was considered inappropriate for the church setting (Robertson, pp. 11-12). No more than fifty requiems were composed in the following century but in the seventeenth century "the number composed is in the hundreds" (Pruett, p. 752).
These new requiems were often very dramatic and by 1621 independent instrumental sections were featured (a break with the primacy of the voice in the plainsong tradition). In many cases composers gave independent attention to the orchestra's role, shifting the focus of attention and advancing the expressive possibilities of the form (Pruett, p. 752). In addition, a number of composers wrote settings for independent sections of the mass, the evocative Libera me was especially popular. These sections could then be added to traditional services where the remaining sections were chanted in plainsong.
In the transition from Renaissance...