According to the original Catholic Encyclopedia, the Abecedarians were a 16th-century German sect of Anabaptists who affected an absolute disdain for all human knowledge, contending that God would enlighten his elect from within themselves, giving them knowledge of necessary truths by visions and ecstasies, with which human learning would interfere.
They rejected every other means of instruction, and claimed that to be saved one must even be ignorant of the first letters of the alphabet; whence their name, A-B-C-darians. They also considered the study of theology as a species of idolatry, and regarded learned men who did any preaching as falsifiers of God's word.
Early Anabaptists were viewed disdainfully by their adversaries as a radical peasant movement (See the Wikipedia article on Anabaptist history). Thus some consider the extant descriptions to be an elitist caricature of either a particular Anabaptist group or Anabaptists as a whole. Most more recent reference works have ceased to mention the group at all. No equivalent entry was present in the New Catholic Encyclopedia. No historical references later than the early 20th century mention these claims.