Roughly translated “enthusiasts”, this English equivalent no longer has the punch it once delivered. Today, “fanatics” would communicate more of the meaning of the German. They are sometimes referred to as those of the “Radical Reformation.” I choose to refer to them here generally as Anabaptists.
While Anabaptists have come to be classed as specific religious groups from the sixteenth century, with contemporary remnant communities found all over the world and known today as Hutterites, Amish, Mennonites, etc., I have a more general meaning in mind when I use the term here. I have reference to a broad third category which has been around since the post-apostolic era. They have generally shared three traits:
(1) they are ultra-separatists and generally recognize no visible institutional expression of catholic orthodoxy, whether Eastern, Western, or Protestant;
(2) they all share a “restorationist” mentality. That is, they are not generally concerned with other historical or cultural expressions of Christianity because they are certain that they alone are a living expression of a primitive, or apostolic, or first century, or original, Biblical Christianity;
(3) they generally do not believe baptism is a sacrament intended for their infants.
From “The Ecclesiastical Text” by Theodore P. Letis (pp. 194-5) [buy]