It seems to have first come into use as one of the hostile names for the "Brethren of the Free Spirit," a pantheistic and generally heretical sect which became prominent in the thirteenth century, and flourished widely, despite destructive persecution, till the fifteenth. Their doctrine being antinomian, and their practice often extravagant, they were accused by Churchmen of licentiousness, so that in their case the name Libertini had its full latitude of application. In the sixteenth century the name of Libertines is found borne, voluntarily or otherwise, by a similar sect, probably springing from some remnant of the first, but calling themselves Spirituales, who came into notice in Flanders, were favoured in France by Marguerite of Navarre, sister of Francis I, and became to some extent associated with sections of the Reformed Church. They were attacked by Calvin in the treatise Contre la sects fanatique et furieuse des Libertins (1544 and 1545). [8] The name of Libertini was not in the sixteenth century applied by any Genevese writer to any political party; [9] but by later historians it was in time either fastened on or adopted by the main body of Calvin's opponents in Geneva, who probably included some members of the sect or movement in question. They were accused by him of general depravity, a judgment not at all to be acquiesced in, in view of the controversial habits of the age; though they probably included antinomian Christians and libertines in the modern sense, as well as orthodox lovers of freedom and orderly non-Christians. As the first Brethren of the Free Spirit, so-called, seem to have appeared in Italy (where they are supposed to have derived, like the Waldenses, from the immigrant Paulicians of the Eastern Church), the name Libertini presumably originated there. But in Renaissance Italy an unbeliever seems usually to have been called simply ateo, or infedele, or pagano. "The standing phrase was non aver fede." [10] In England, before and at the Reformation, both "infidel" and "faithless" usually had the theological force of "non-Christian." Thus Tyndale says of the Turks that though they "knowledge one God," yet they "have erred and been faithless these eight hundred years"; adding the same of the Jews. [11] Throughout Elizabeth's reign, "infidel" seems thus to have commonly signified only a "heathen" or Jew or Mohammedan. Bishop Jewel, for instance, writes that the Anglo-Saxon invaders of Britain "then were infidels"; [12] and the word appears to be normally used in that sense, or with a playful force derived from that, by the divines, poets, and dramatists, including Shakespeare, as by Milton in his verse. [13] Ben Jonson has the phrase: I did not expect To meet an infidel, much less an atheist, Here in Love's list. [14]