Catholic priestly celibacy was codified at the second Lateran Council in 1139. Before this time there was great diversity in practice in different locations. You had theological justifications for the practice which included Christ's and various apostles' appeals for celibacy as a way of focusing on religious rather than worldly matters. There were also scandals by which large amounts of church property were inherited away from it by priests who had many children which lead directly to a previous decree in the early 11th century by Pope Benedict VIII that the children of priests could not inherit property.