From the longer Wikipedia page  which has a list of references.
The Lead Books of Sacromonte (Spanish: Los Libros Plúmbeos del Sacromonte) are a series of texts inscribed on circular lead leaves, now considered to be 16th century forgeries.
The Lead Books were discovered in the caves of Sacromonte, a hillside outside the old city of Granada, Spain, (Wikipedia page ) between 1595 and 1606. They comprise 22 volumes of inscribed circular lead leaves, laced together with lead wire and bound within folded lead covers. They were found together with burned human remains, identified by lead plaques as being those of Caecilius of Elvira and eleven followers, supposedly martyred under the Emperor Nero. References in the books claim that they were inscribed by Arabic-speaking Christians during the Roman period, and deposited with the martyrs' remains.
The Lead Books appeared to be written in a combination of Arabic and Latin, using characters that 16th century Morisco scholars claimed to recognise as "Solomonic" and which they identified as pre-Islamic Arabic. Many letter forms were uncertain, and the texts themselves were cryptic and obscure, so the Catholic authorities found themselves entirely reliant on Morisco translators; chief amongst whom were Miguel de Luna and Alonso del Castillo, who by fortunate chance lived in the nearby Albaicin, and who had indeed been instrumental in the rediscovery of some of the books. One complete book, the so-called "Libro Mudo", or "Mute Book", has remained undeciphered and untranslated to this day.
Early 17th century Protestant scholars in the Netherlands also took a keen interest, but their characterisation of the Lead Books as a blatant fabrication only served to discredit dissenting opinions within Catholic Spain by association with heresy. The Vatican remained highly sceptical of the texts, however, and in 1642 succeeded in having the Lead Books sent to Rome, together with an associated "ancient" parchment which had been discovered in 1588 in a lead box in the tower of a former mosque in the city of Granada itself. A prolonged investigation by the Holy Office in Rome concluded in 1682 that both the parchment and the Lead Books were heretical forgeries. While the Vatican's condemnation did not implicate any specific individuals, scholarly consensus since the sixteenth century is that the forgers were probably Luna and Castillo, the same two Moriscos who had translated many of the texts. While further discussion of the books by Catholics was officially forbidden, some Spanish scholars continued to maintain the authenticity of the texts through till the 19th century. The Lead Books were kept in the Vatican, but eventually returned to the Abbey of the Sacromonte in the year 2000. The Church authorities in Granada continue to forbid scholarly access however, on the grounds that the official prohibition remains in force. Current studies depend on the various (often partial and highly contradictory) transcripts and translations made at the time of the books' discovery, and on some independent decipherments produced by Vatican Arabists.
Almost all scholars now concur with the official verdict and believe that the books are a forgery intended to promote toleration of the language, dress and customs of Christian Moriscos in the face of increasing hostility from the Spanish Inquisition and the Castilian state. If so, this exercise was unsuccessful in its general objective, as between 1609 and 1614 the entire Christian Morisco population of Andalucia, estimated as 250,000 persons, was deported, and, although some were allowed to settle in Italy, most eventually found their way to North Africa or Turkey, where they reverted to Islam. Both Castillo and Luna escaped this fate, as the archbishop of Granada, Pedro de Vaca de Castro y Quiñones, grateful for the immense increase in the prestige of his see arising from the discovery of the relics of St Caecilius, extended his personal protection to them and their families. Many of the deported Moriscos remained convinced of the books' authenticity however, and transcripts continued to circulate within Tunisia, until this practice was forcibly suppressed by Islamic religious authorities there.