During the sixteenth century there were many religious colloquies involving Protestant and Roman Catholic theologians. These all sought the elusive goal of a religious settlement that would enable both sides to coexist in a united church. The most famous of these colloquies took place at Regensburg in 1541, resulting in the remarkable phenomenon of an agreed statement on justification by faith alone.

The modern reader may wonder that was the point of these debates. Was it not clear that there could be no common ground? The answer is that it might be clear to us, with the benefit of hindsight, but it was not at all clear at the time. In the latter part of the sixteenth century Europe divided into rival confessions: Roman Catholic, Lutheran, Reformed. With hindsight that can appear an inevitable outcome, but it did not appear to be inevitable at the beginning and even today we cannot say with certainty that is was an inevitable outcome. Protestantism eventually resolved into Lutheran versus Reformed but it was not inconceivable that the more moderate elements might have united behind a Protestant confession. The division between Protestant and Roman Catholic was more substantial -- though not so substantial before the Council of Trent (1545-63) as after it. Most of the participants of the colloquies on each side were Erasmian humanists, sharing a concern to reform the church by going behind the middle ages to the sources of the golden age of the church, the Bible and the Early Fathers.

There was every incentive to strive for agreement. While many today might suppose that when Jesus prayed that his church might be one (John 17) what he really meant was "let there be a competing market of hundreds of different denominations", that was not how it was understood in the sixteenth century. There was a belief that the church was meant to be one and that division was a scandal. The Reformers' aim was not to found a new church in opposition to the Catholic Church (let alone a plethora of churches) but to reform the Catholic Church. The desired outcome was not a church or churches to which people might belong were they so to desire, but a single church in each locality to which all citizens would belong. The Anabaptists had a very different aim, of course, but they were not involved in the colloquies.

The greatest chance of success came in three gatherings that were held in 1540 and 1541. These began with a colloquy at Hagenau in June and July 1540, which was adjourned to Worms. There it met in November and after long delays Melanchthon and Eck began to debate original sin in January and agreement was reached in a few days. At this point Nicholas Perrenot de Granvelle, the imperial chancellor, adjourned the debate to the coming Diet at Regensburg. Meanwhile at Worms secret discussions had been taking place (chiefly between Gropper and Bucer) to draw up the Regensburg Book, a collection of twenty-three articles, which was to be used as a basis for further discussion.

The anticipated colloquy took place at the Regensburg Diet, which opened on 5 April. Gasparo Contarini was present as the papal legate. The emperor selected the debaters: Bucer, Melanchthon and Pistorius on the Protestant side; Gropper, Eck and Pflug on the Catholic side. Others, like Calvin and Pighius, were present but not selected as debaters.

Bucer and Gropper were appointed as conciliators with the potential for reaching agreement. Bucer was the most flexible of the Protestant negotiators. Melanchthon and Eck were appointed as hardliners, whose presence was necessary for the credibility of the proceedings. Melanchthon came with strict instructions not to deviate from the Augsburg Confession. Pistorius and Pflug were both chosen as moderates with the aim of keeping Melanchthon and Eck in the minority. Pistorius, however, is more often than not described as siding with Melanchthon against Bucer's over-readiness to make concessions.

At the Emperor's insistence, the Regensburg Book became the basis for discussion. Its origin was a closely guarded secret, the Emperor stating that it had been composed by learned theologians in Flanders. On 27 April the first four articles, on human innocence before the fall, free choice, the cause of sin and original sin were quickly agreed, building on the Worms agreement. The fifth article, on justification, was discussed from 28 April to 2 May. Eck and Melanchthon both found the Worms Draft unsatisfactory and it was eventually agreed it should be set aside and that there be free discussion to draw up a new article. During the discussions Melanchthon, Eck and Gropper each produced drafts.

Eventually, on 2 May, a version was produced (drawing heavily on Gropper's draft) to which all the parties gave their consent. Granvelle and Contarini were jubilant and the latter expressed his joy to Cardinal Alessandro Farnese (the pope's grandson) in Rome: "God be praised, these Catholic and Protestant theologians resolved to agree on the article of justification, faith and works." Eck needed some persuasion to sign. In the words of one modern scholar, "at Regensburg the Wittenberg Reformation and the reforming strand of the ancient Italian Church joined hands." The initial response was predominantly positive. The Protestant Elector of Brandenburg even sent his musicians to serenade Contarini!

The joy and the hope engendered were to be short-lived. The colloquy soon began to founder, but that was because of differences on other doctrines, such as the infallibility of councils and transubstantiation, not because of shortcomings in the statement on justification. Ironically, it was the same Contarini who was willing to be flexible over justification who torpedoed the colloquy by his intransigence over the word transubstantiation. He insisted on its insertion and would not countenance any compromise. He rejected Granvelle's suggestion that discussion of the word be deferred to the end of the colloquy. While the doctrine of justification had not been defined by the church, transubstantiation had been proclaimed by the Fourth Lateran Council. Ultimately, as always, the colloquy foundered over the question of authority. On 22 May the colloquy came to a close, the article on justification being its only significant achievement. On the 31st the revised version of the Regensburg Book was delivered to the Emperor, together with nine new articles that the Protestants had composed in opposition to some of the articles in the Book that had not been agreed.

Protestant reactions to Article 5 were mixed. Luther (who was not present) branded it patched and all-embracing. He claimed that the two ideas of justification by faith alone without works and faith working through love had been thrown together and glued together. This is like sewing a new patch onto an old garment. Calvin (who was present) was much more positive:

On the Catholic side Contarini continued to commend and defend the article, as did Gropper and Pflug. Eck sought to distance himself from it. In Rome the pope did not want it to be widely seen so it was not read in consistory. Those who did see it said that though the sense might be Catholic, the wording was too ambiguous. The pope neither approved not disapproved the article. It is noteworthy that in these early stages the charge against Article 5 was ambiguity, not unorthodoxy, and even the hard-line Cardinal Carafa (later Pope Paul IV) thought that it could be given a Catholic interpretation.

Essentially both the Protestant and Catholic responses were twofold. Some maintained that the Regensburg article was compatible with their own teaching. Others regarded it as a compromising patchwork that was dangerously ambiguous rather than actually false. Both sides agreed that further explanation was necessary. They were concerned not so much about the content of Article 5 as fear of how the other side would exploit it.

The goal of the colloquy was agreement across the board, not on one article only. The enthusiasm that greeted Article 5 was enthusiasm for the prospect of agreement across the board, not enthusiasm for the idea of agreeing in one point only. Events were soon to prove how unrealistic this was. After the breakdown of the colloquy those who had been willing to make concessions were criticised by their own sides. On all sides conciliation gave way to recrimination as the participants published works focusing not on the limited agreement reached but on the reasons for the failure of the colloquy.

The breakdown of the Regensburg Colloquy revealed the irreconcilable nature of the split between the two sides. One response was the reorganisation of the Inquisition in 1542. Conciliation and negotiation had failed. The need now was for clear lines of demarcation. It was with that in mind that the Council of Trent (1545-63) was called. This set out to define Roman Catholic dogma in a firmly anti-Protestant manner, as in the Decree on Justification (1547).