Your very own Rad Trad, one in the interminable and ever-growing plethora of internet "liturgists," has just begun plugging through Msgr. Pierre Batiffol's History of the Roman Breviary, first published in 1893 and re-published in 1895 and 1913—the latter with a new conclusion after the 1911-1913 Office reforms. The Rad Trad realizes that the work's integrity is over a century old and probably somewhat dated, but that does not mean it is without merit or value today. The first chapter has a very nice patristic overview of the origins of the various hours of the Divine Office, both in their timing and in their contents. Msgr. Batiffol covers the ancient practice of nocturnal vigils (hence where we get the term "nocturne" for the segments of Mattins) and the later coming of Vespers and Lauds. Sacred architecture and vast public worship spaces gave rise to antiphonal and metric singing as well as concluding doxologies (Gloria Patri et Filio....), replacing the pre-313 days of a solitary lector reciting a psalm at a time. Public piety and the eagerness of virgins and ascetics to pray throughout the day wrought Terce, Sext, and None. These people later became monks and, finding periods of free time between the daytime and nighttime prayers, began to slacken their discipline. Compline and Prime filled that free time. The succeeding chapter are similarly interesting. Best of all the History of the Roman Breviary is in the public domain and free for pdf download here! Take a look.