A Dictionary of Music and Musicians/Deus Misereatur
DEUS MISEREATUR is the psalm (lxvii.) used in the evening service of the Anglican church after the lessons, alternatively with the Nunc Dimittis. It is considered as a 'responsory psalm' in conformity with the 17th canon of the Council of Laodicea, which appointed lessons and psalms to be read alternately.
In the ancient church the psalm was used at Lauds, and in the Sarum use it was coupled with the bidding prayer on Sundays. Nevertheless it is not in Cranmer's Prayer-Book of 1549, and consequently has no special chant given for it in Marbecks 'Book of Common Prayer Noted,' of 1550. It was appointed as an alternative to the Nunc Dimittis in the revised edition of the Prayer-Book, 1552. Like its fellow, the 98th Psalm, it is not so often used as the 'Nunc Dimittis,' partly because it seems less appropriate than that canticle, and partly because it is longer.
Settings of it are comparatively rare. To take for example the most famous ancient collections of services; there is only one setting in Barnard's collection, viz. that by Strogers; there are three in Boyce's, and only two in Arnold's. With regard to the setting in Barnard's collection, it is worth remarking that there is a quaint note at the end of the index suggesting that it should be sometimes used as an anthem.