Which Catholic saint's Rule became a foundational guide for Western monasticism?

Benedict of Nursia wrote the Rule that became a foundational guide for Western monasticism.

Benedict was born around 480 in Nursia, in central Italy, and became a monk after leaving his studies in Rome. He established monasteries, including Monte Cassino, traditionally dated to around 529. His Rule organized communal life around prayer, work, obedience, stability, and the authority of an abbot.

The Rule was not the only monastic rule in early medieval Europe, but it became especially influential through later adoption and promotion. Benedictine monasteries helped preserve learning, develop schools, and shape European religious culture. Benedict died around 547 and is regarded as the principal patron of Europe, a title given jointly with other saints by Pope Paul VI in 1964.