Christianity in iran spreaded during the Parthian (Ashkanian) period. Christians of iran played a significant part in the history of Christian mission. There are still old churches found in iran. The church of St.Mary’s in north western is said to be the second oldest church next to the church of Bethlehem in Palestine. Iran is home to one of the world’s oldest continuous major civilizations.

The area of Christian theology focusing on the nature of Jesus as the Christ, particularly with how the divine and human are related in his person, is known as Christology. A central doctrine within the Trinitarian (Nicene) interpretation is that God took human form in the body of Jesus, "the Christ," and accordingly "Christ" was or is both fully human and fully God. Following from this association between God and Jesus, many Christians believe that belief in Jesus either qualifies them as inheritors of a special privilege or else provides for them a conceptual interface to God’s being, such that translates to having a greater "personal relationship" with God. Further, these concepts of personal connection with God have claimed relevance, in varied denominational doctrines, to fundamental spiritual concepts including God’s love, divine providence, divine illumination and even salvation.