The office's history after Benedict is a history of compression and recovery. The medieval hours grew so elaborate that the travelling clergy of the new mendicant orders needed the whole apparatus in one portable book, the breviary, and with portability came privatisation: an office designed as the church's common prayer became, for most clergy, a daily obligation discharged alone. Trent standardised the Roman Breviary in 1568; Pius X redistributed the psalter in 1911; and the Second Vatican Council ordered the deepest reform since antiquity.
The Liturgy of the Hours promulgated in 1971 renamed and restructured the cycle: Lauds and Vespers were declared the two hinges of the day, Matins became an Office of Readings usable at any hour, Prime was suppressed outright, the psalter was spread over four weeks instead of one, and the vernacular was admitted, changes aimed at returning the office to parishes and laity rather than leaving it a clerical burden. The other traditions ran parallel courses.
The Byzantine East never broke its cycle, keeping vespers, compline, the midnight office, orthros and the four little hours in the Horologion. The Book of Common Prayer distilled the old offices into Morning and Evening Prayer, and choral Evensong remains Anglicanism's most distinctive liturgical gift. The modern revival of daily prayer apps and printed lay editions means the office is now prayed by more people than at any time since the age in which it was built.