One, Holy, Catholic, and Apostolic Church

The Four Marks of the Church is a term describing four specific adjectives—one, holy, catholic and apostolic—indicating four major distinctive marks or distinguishing characteristics of the Christian Church. The belief that the Church is characterized by these four particular "marks" was first expressed by the First Council of Constantinople in the year 381 in its revision of the Nicene Creed, in which it included the statement: "[I believe] in one, holy, catholic, and apostolic Church." In Protestant theology these are sometimes called the attributes of the Church. They are still professed today in the Nicene Creed, recited in the liturgy of Catholic, Orthodox, Anglican, and many Protestant churches' worship services.

While specific doctrines, based on both tradition and different interpretations of the Bible, distinguish one Church or denomination from another, largely explaining why there are so many different ones, the Four Marks, when defined the same way, represent a summary of what historically have been considered the most important affirmations of the Christian faith.

The ideas behind the Four Marks have been in the Church since early Christianity. Allusions to them can be found in the writings of 2nd century early Church Father and bishop, Ignatius of Antioch. They were not established in doctrine until the First Council of Constantinople in 381 as an antidote to certain heresies that had crept into the Church in its early history. There the Council elaborated on the Nicene Creed, established by the First Council of Nicea 56 years before by adding to the end a section that included the affirmation: "[We believe] in one, holy, catholic, and apostolic Church." The phrase has remained in versions of the Nicene Creed to this day.

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