Edward J. Quigley, The Divine Office: A Study of the Roman Breviary
“ Thus he may be counted as a reformer, but not as an innovater nor an abridger. But his reform fell on evil days. The great struggle between Church and State about lay investitures had a baneful influence on liturgy, even in Rome itself. The times seemed to call for a modernised (i.e., a shortened) office. The "modernisers" respected the psalter, the curtailment was in the Lectionary. The modernising spirit showed itself in the arrangement and bulk of the office books. The Psalter, Antiphonary, Responsorial, Bible and Book of Homilies were gradually codified. ”
