 The term "Unitarian" first appeared as "unitaria religio" in a document of the Diet of Lécfalva, Transylvania on 25 October 1600, though it was not widely used in Transylvania until 1638, when the formal "recepta Unitaria Religio" was published.The Polish Brethren began as a grouping of Arians and Unitarians who split from the Polish Calvinist Church in 1565, though by 1580 the Unitarian views of Fausto Sozzini (hence the adjective Socinian) had become the majority.Sozzini's grandson Andrzej Wiszowaty Sr. in 1665-1668 published "Bibliotheca Fratrum Polonorum quos Unitarios vocant" ("Library of the Polish Brethren who are called Unitarians" 4 vols.