Water was regarded as the best protection against ghosts. The Romans carried water three times around the corpse; in the twentieth century the body is sprinkled with holy water, and hand washing at the cemetery is still a Jewish ritual. Baptism was a feature of the later water ritual; primitive bathing was a religious ceremony. Only in recent times has bathing become a sanitary practice.  Baptism became a religious ceremonial in Babylon, and the Greeks practiced the annual ritual bath.  Jews had long been the practice to baptize the gentile proselytes into the fellowship of the outer court of the temple. 
The apostles of Jesus and John unanimously voted that baptism would become the initial step in the outward alliance with the affairs of the kingdom, a public profession of entrance into the kingdom.  Jesus never baptized anyone. This task was only done by the apostles and their followers. 
In early Christian church at first they baptized in the name of Jesus; it was almost twenty years before they began to baptize in “the name of the Father, the Son, and the Holy Spirit.” Baptism was all that was required for admission into the fellowship of believers.  Mithraism shared with christianity a baptism and a sacrament with bread and wine.