Christianity has often defined itself historically by what it is not, as much as by what it is. The modern Christian Church of the late 19th early 20th centuries struggled to define itself dogmatically. From an American religious perspective, heretical controversies defined the times. This paper specifically focuses on the move away from what some considered as the orthodox, historical, Christian doctrine in the modern era by two late 19th and early 20th century churchmen. Historical context is therefore important considering this unique period in American religious history. The study draws upon research about Charles Augustus Briggs’ trials within the Presbyterian Church that transpired between 1891 and 1893. It also focuses on Algernon Sidney Crapsey’s heresy trial in 1906-1907 in the Protestant Episcopal Church. It further considers the historiography of the trials by examining the interpretations of various historians concerning this epoch in American religious history.