Of the many prophetic and polemical works that were attributed to Joachim in the 13th and following centuries, only those enumerated in his will can be regarded as absolutely authentic. These are the Concordia novi et veteris Testamenti (first printed at Venice in 1519), the Expositio in Apocalypsin (Venice, 1527), the Psalterium decem chordarum (Venice, 1527), together with some "libelli" against the Jews or the adversaries of the Christian faith.
It is very probable that these "libelli" are the writings entitled Concordia Evangeliorum, Contra Judaeos, De articulis fidei, Confessio fidei and De unitate Trinitatis.
Spottiswoode published in 1620 Refutatio libelli de regimine ecclesiae scoticanae, an answer to a tract of Calderwood, who replied in the Vindiciae subjoined to his Altare damascenum, (1623).
The Scriptores are divided into A uctores antiquissimi, Scriptores rerum Merovingicarum, Scriptores rerum Langobardicarum et Italicarum, Libelli de lite imperatorum et pontificum, Gesta pontificum Romanorum and Deutsche Chroniken, or Scriptores qui vernacula lingua usi sunt.
But the church was thereby involved in a double conflict; for while on the one hand the Novatianist schism represents the puritan outcry against such laxity, on the other the martyrs (not indeed for the first time) claimed a position above church law, and gave trouble by issuing libelli pacis, i.e.
Dummler in Monumenta Germaniae historica, Libelli de lite imperatorum et pontificum saeculis xi.
250, evaded the consequences of their Christian belief by procuring documents (libelli) which certified that they had satisfied the authorities of their submission to the edict requiring them to offer incense or sacrifice to the imperial gods.
Archbishop Benson is probably right in thinking that "there was no systematic and regular procedure in the matter," and that the libelli may have been of very different kinds.
With such libelli we are not here concerned.] The subject has acquired a fresh interest from the fact that two of these actual libelli have been recovered, in 1893 and 1894 respectively, both from Egypt; one is now in the Brugsch Pasha collection in the Berlin Museum; the other is in the collection of papyri belonging to the Archduke Rainer.
But no doubt libelli in this same form were delivered, in Egypt at least, to Christians who secured immunity without actual apostasy; and the form in Italy and Africa probably did not differ widely from this.