Pachomius the Great

Anthony invented solitary monasticism. Pachomius invented communal monasticism — the monastery as an organised community with a rule, a schedule, shared meals, and a superior. Around AD 320 in Upper Egypt he gathered hermits into walled compounds and gave them a structure that scaled. By the time he died there were thousands of monks living under his rule across nine monasteries. Basil borrowed from him for the East. Benedict borrowed from him (via Cassian) for the West. Every cloister you've ever seen — every Benedictine, Cistercian, Carthusian, Trappist house — is a descendant of what Pachomius set up in the Egyptian desert.