Pachomius also formalized the establishment of an "abba" (father) or "amma" (mother) in charge of the spiritual welfare of their monks and nuns, with the implication that those joining the monastery were also joining a new family. Members also formed smaller groups, with different tasks in the community and the responsibility of looking after each other's welfare. The new approach grew to the point that there were tens of thousands of monks and nuns in these organized communities within decades of Pachomius' death. One of the early pilgrims to the desert was Basil of Caesarea, who took the Rule of Pachomius into the eastern church. Basil expanded the idea of community by integrating the monks and nuns into the wider public community, with the monks and nuns under the authority of a bishop and serving the poor and needy.