Simplify the following text for a Grade 12 native English-speaking person.
Original: Doubt has been cast on this explanation of the origin of the familiar Niceno-Constantinopolitan Creed , commonly called the Nicene Creed . On the basis of evidence both internal and external to the text , it has been argued that this creed originated not as an editing by the First Council of Constantinople of the original Nicene Creed , but as an independent creed ( probably an older baptismal creed ) modified to make it more like the Nicene Creed of 325 and attributed to the Council of 381 only later .
Simplified: The Nicene Creed , Niceno-Constantinopolitan Creed or Icon\/Symbol of the Faith , is the most widespread or ecumenical Christian statement of faith .