The Benedictines were defined by the Regula Benedicti. Other medieval orders drew inspiration from the example of charismatic founders, from spiritual charters, and from a succession of congregational (episcopal and papal) constitutions, but none of them was bound to a single code. The RB gave a complete account of the monastic vocation, from the rejection of the world (RB, prologue) to the final reunion with God (‘ad patriam caelestem’: RB, lxxiii). Remarkably, for a text whose transmission and translation was uninterrupted for a millennium the RB also retained its coherence; from the time it first came together as a sequence of chapters, there were never accretions or interpolations to the text and commentators sought not to correct but to contextualise the precepts of the founder. Perhaps above all the RB provided a simple introduction to the professed life, accessible to any condition and applicable – notwithstanding a slight Mediterranean orientation – to any clime or community. These qualities ensured a degree of continuity in Benedictine observance that eluded other orders: over the course of the Middle Ages capitular, episcopal and papal authorities sought to renew the regular life but never to reinvent it. The demands of the Benedictine day in the second quarter of the sixteenth century would have been familiar to the followers of Benedict of Aniane, and perhaps by the pioneers of the first Montecassino. Of course, the clarity of the code presented superiors, ecclesiastical supervisors, and secular patrons with a measure of pure Benedictinism with which the professed might be judged. When material conditions, and their institutional consequences, compromised communal observance in later centuries, the RB was sometimes read as a record of monastic decline.

The Benedictines were neither the progenitors nor the first pioneers of the regulated life. Benedict's rule was shaped by the cenobitic customs of his time, and from the traditions of Latin, Greek and Middle Eastern monasticism. These early regulae were reflected not only in the form of Benedict's cenobium, a community of brethren sharing one profession under the supervision of a single head, but also in the scope of its horarium (i.e. daily schedule), a balance between spiritual and bodily labours, opus Dei and opus manuum. Early eastern practice was also echoed in the ascetic regime of RB: abstinence from meat and further restrictions on food, sleep and speech recalled the Egyptian eremites.