The Office, in the broad sense of the word, was prayed by the Christian Church from the dawn of her existence. Paul and Silas sang psalms in the prison in full voice so that other people could hear it (Acts 16:25). The Office, in the strict sense of the word, was born when the constituents above have been integrated and the continuous psalmody has been built organically into the regular “Folk Office.” This historical process was affected by the foundation of urban monasticism: the monks moved into the cities and became catalysts of the “pastoral” liturgy, and consequently, of the Parish Office. Simultaneously, once the persecutions stopped, the parish churches were provided with priests, deacons, acolytes, lectors, psalmists, and so became able to sing the full Office day by day, and to pray it not only with the people (cum populo), but also for the people (pro populo).
The coalescence of the components proved very successful. The continuous psalmody provided a stable order and tranquility to the Office, and it also corresponded to the obligation of the periodic recitation of the full Psalter. The “Parish Office” offered a stable framework to composition, made it possible to recite the outstanding psalms more frequently, added influential elements and rituals to the psalmody, and increased its beauty along with its efficacy. This well-balanced, we may say, classic arrangement of the Office was achieved in the 4th and 5th centuries, was uniform over the entire Christian world in its essential motives, while the actual solutions differed according to the great ecclesiastical provinces.
Perhaps the most mature construction in the realm of Office varieties is the proper Office of Rome. Its elements were ready by the 4th , or at the latest, by the 5th century. When St. Benedict of Nursia gave an Office to his monks (beginning of 6th century), he had no more to do than to adapt the Roman Office to the living conditions of the monastery. This 4th-5th-century form of the Roman Office has been augmented during the subsequent centuries, and it eventually gave birth to a great family of various related Offices, while in essence it remained unchanged up until the 20th century. What is meant by the term “Roman Office” is this 1500-year old structure, yet not any one individual form of it (like the Tridentine Office), but the totality expressed in the rites of dioceses and religious orders. In this sense it can be said that the Roman Office – originated in the 4th or 5th century – was deadly wounded around 1900, and ceased to exist in 1970.
Laszlo Dobszay, The Bugnini-Liturgy and the Reform of the Reform (2003)