The desolate region became one of Christianity's most sacred areas. The desert fathers and cenobitic monastic communities used the desert's solitude and privations to develop self-discipline (asceticism). Hermit monks believed that desert life would teach them to eschew the things of this world and follow God's call. Between the 4th and 7th century A.D., hundreds of thousands of people from the world over joined the hundreds of Christian monasteries in the Nitrian Desert, centered on Nitria, Kellia and Scetis (Wadi El Natrun).