“The original acts of the Council, as prepared by its general secretary, Bishop Angelo Massarelli, in six large folio volumes, are deposited in the Vatican, and have remained there unpublished for more than three hundred years. But most of the official documents and private reports bearing upon the Council were made known in the sixteenth century, and since…The history of the Council was written chiefly by two able and learned Catholics of very different spirit: the liberal, almost semi-Protestant monk Fra PAOLO SARPI, of Venice (first, 1619); and, in the interest of the papacy, by Cardinal SFORZA PALLAVICINI (1656), who had access to all the archives of Rome.” Creeds of Christiandom, Schaff
“By Massarelli's diligence, no Council in Church history was better documented. But at that date, probably with the intention of silencing unnecessary discussion about predestination and grace, popes consciously adopted the policy of allowing no one to consult these papers. Not to make them available became an established rule of the Roman Curia.” (C & H, pg. 46)
Pallavicino’s History was Rome’s answer to Sarpi’s very popular work and became the excuse to not allow access to the Vatican’s documents on Trent for many years. However, as time went on, private collections of documents concerning Trent began to emerge publically, influencing Rome's stance.
“Everywhere documents were published - except from the place where the best documents lay. Historians see the past through the eyes of the authors of the archives which they use. Pallavicino - it was later seen as a defect - saw Trent only through the eyes of cardinals then in Rome. But now men were seeing Trent through the eyes of men in Madrid or Paris or Vienna. Pressure built up, that Rome must publish all, or at least more, of the original documents of the Council of Trent. No project could be dearer to Theiner. He persuaded Pope Pius IX that publication was desirable if not necessary. The Pope appointed a commission with a Dominican cardinal as chairman, and the commission (April 1857) reported favourably.” (C & H, pg. 49)
With this approval, Theiner moved forward with his work on Trent with the intent of publication. But as the details of the Council uncovered by Theiner came forward, the tide began to change with regards to approval,
“That autumn the course of the commission did not run smoothly. Some of the speeches at Trent, which Theiner wanted to publish, contained doubtful matter, even of uncertain orthodoxy. The Dominican chairman Cardinal Gaude asked Theiner to insert footnotes to refute what was wrong or explain what might be misunderstood. Theiner's sense of integrity was offended. He rejected such footnotes, and won… That winter of 1857 the commission, appointed to advise, suddenly recommended that the plan be suspended. One member of the commission, Father Tosa the Dominican, who began by being hesitant and soon was enthusiastic, suddenly turned against the scheme. The commission saw sheets already printed, and changed its mind.” (C & H, pg. 49-50)
Why the change of heart? Apparently, the discussions at the Council as documented by Massarelli provided detail that the commission felt could undermine the authority of the Church. The reaction of the commission gives some interesting insights into the discussions at Trent around both the canon of Scripture and Tradition:
“Massarelli reported what was said. He recorded the differences of opinion, the follies as well as the wisdom of the speakers, the unedifying as well as the edifying. If Massarelli's diaries were published, the decisions of the Council of Trent, sacred in so many minds, would no longer appear the unchallenged expression of a common Catholic mind, but the end of hard-fought debates over nuances of expression. Only the result had authority, not the course of events or utterances which led to the result. The upholders of Pallavicino maintained that to publish Massarelli could do nothing but weaken the authority of the canons of Trent, as well as the official history by Pallavicino. This was particularly true of the early debates on scripture and tradition, the authority of scripture, and its canon. In the cold light of finality, the formulas look rigid against Protestants. Seen as the end of a long debate with differing opinions, the formulas have more nuance, more flexibility, than any Protestant hitherto supposed. The examining commission particularly objected to the minutes which Theiner proposed to publish, and had already in proof, of the debate on the canon of holy scripture. Thus the Dominican Father Tosa, lately an enthusiast, became the main speaker on the commission of enquiry, that to publish was dangerous, or harmful to the Church. He said emphatically that to print these minutes could hand weapons to Protestantism to attack the Catholic Church and the Council of Trent. By the autumn of 1857 Tosa sufficiently carried the day for the commission to recommend suspension of the plan.” (C & H, pg. 50-51)
After the commission's decision, Theiner appealed to the Pope and continued to attempt to publish his work, but he ultimately failed to get approval. He later fell out of grace with the Vatican due to suspicion that he had passed on documents concerning the order of business at Trent, documents that were being suppressed by the Curia to avoid any effect on the Vatican I Council.
The short-lived potential of Theiner's original work is evident in the Journal of Sacred Literature, dated October 1857, which contains an announcement for the expected publication of the Theiner’s work:
“...The result is, that the Pope has consented to its publication, and added ten thousand scudi to aid in the project, and besides has re-instituted the famous printing- press of the Vatican, which will commence its new life with Padre Theiner's Complete History of the Council of Trent, and with the publication of all the original documents which have been so long kept from vulgar gaze among the countless MSS. of the Vatican. The first part will appear in three folio volumes, containing the complete diary of the Council as it was arranged by Signor Massarelli, the secretary, and signed by the fathers themselves; also the acts of the Council, from its formation on the 13th December, 1545, to its close on the 4th December, 1563, with all the disputes, controversies, and correspondence during that time. These acts are now for the first time presented to the world in an unmutilated form.”
Unfortunately, for Theiner, that day never came. After his fall from grace, Theiner was able to move much of his work on the Council of Trent out of Rome and with the help of friends, worked towards private publication. However, the scope of his work was much reduced from the initial expectations some fifteen years earlier (just two volumes instead of the anticipated seven). Theiner died just prior to the publication in 1874 of his Acta genuina ss. oecumenici Concilii tridentini. It wasn’t until 1901 when the first volume of Concilium Tridentinum was published that "the world" would finally have access to the full Acts of the Council of Trent (over many volumes/years).