Even Villages Had a Temple
Another factor that strengthened the unity of the early village was the temple and its service. The immigrants from the north either brought with them or developed not long after their arrival an abiding faith in one special deity as the protector of their settlement, and with the building of their first houses they also erected a home for their divinity. For example, underlying the ruins of Eridu, one of Sumer’s most venerated cities, archeologists unearthed a mud-brick temple built on virgin soil by the original Ubaidian inhabitants. It was a small rectangular shrine, about 15 feet long, and its furnishings consisted of nothing more than a crude altar and an offering table. But as the villages prospered through agriculture and expanded into sizable towns, such humble shrines were enlarged into elaborate structures each set atop a lofty mud-brick platform, a prototype of the future ziggurat, or temple-tower. Each temple served an entire community, rather than an individual family or clan, and thus generated and intensified local patriotism, pride and effort.
Nor was the temple merely an edifice of lifeless brick and mortar; it was a holy place that had to be tended and cared for every day, year in and year out. Hymns and prayers had to be composed, formalized and recited; rites and rituals had to be performed; sacred festivals had to be celebrated. And so a specialized priesthood came into being, starting no doubt with the selection of one or two individuals noted for their learning and spiritual powers and proliferating in number and function over the centuries. In the course of time the temple and its priestly coterie naturally became the intellectual center of each community, and it is therefore not surprising that it was in the temple that writing was later invented and developed.
— Cradle of Civilization, pp. 33-34