Later interaction between Christianity and mystery religions did take place. Christianity has its own initiation ritual, baptism, and beginning in the fourth century, Christians began to refer to their sacraments, such as baptism, with the word "mysterion", the Greek term that was also used for a mystery rite. In this case, the word meant that Christians did not discuss their most important rites with non-Christians who might misunderstand or disrespect them. Their rites thus acquired some of the aura of secrecy that surrounded the mystery cults.