Some of them were before the trinity was defined in the year 325 Nontrinitarianism was later renewed in the Gnosticism of the Cathars in the 11th through 13th centuries , in the Age of Enlightenment of the 18th century , and in Restorationism during the 19th century . Nontrinitarianism was later renewed in the Gnosticism of the Cathars in the 11th through 13th centuries , in the Age of Enlightenment of the 18th century , and in some groups arising during the Second Great Awakening of the 19th century .