We are pleased to share a recent piece at The Gospel Coalition by Chris Castaldo, with the permission of Castaldo and Dr. Ryan M. Reeves. Castaldo highlights some fundamental divisions among Protestants and Catholics by exploring the role of one Catholic cardinal at Regensburg.
What is the fundamental difference between Roman Catholic and evangelical Protestant faith? The story of Cardinal Gasparo Contarini at Regensburg illustrates the answer.
Trained in philosophy at the University of Padua, Contarini (1483-1542) became a champion of evangelical renewal in Italy. While much can be said about his career as an imperial diplomat, his elevation to the role of cardinal (1535), and his advocacy of the new Jesuit order (1540), we shall focus on his interaction with Protestants around the gospel.
Contarini Among Friends
Contarini enjoyed discussing theology with friends. On one occasion, his friend Tomasso Giustiniani wrote Contarini distressed that the Camaldoese Order of Hermits, which Giustiniani had recently entered, failed to provide certainty of salvation. This news deeply troubled Contarini and led him to reexamine his faith. Like Luther, Contarini’s crisis revolved around the question of how one secures divine forgiveness.
A ray of hope eventually pierced Contarini’s dark cloud of doubt. It was “on Holy Saturday of 1511” when he “experienced a moment of illumination” that was likened to Luther’s epiphany, where “he was fully convinced that salvation could not be won by any human act but was God’s free gift; and, as in Luther’s case, this conviction was accompanied by a perception that the monastery could not, for himself, procure an eternal blessedness.” This discovery left Contarini awestruck. The 20th-century Catholic historian Hubert Jedin has described it as a “tower experience.” As with Luther, this awakening led Contarini to a doctrine of imputation. But unlike Luther, it also inspired an ecumenical spirit.
The Original Evangelicals and Catholics Together
Contarini’s opportunity to engage Protestants in ecumenical dialogue came in April 1541 when Charles V organized an imperial conclave to unify his empire against threats from the outside. The Emperor simultaneously engineered a theological conference at Regensburg to accompany diplomatic sessions. Given the integral relationship of church and state in the pre-modern era, religious solidarity between Roman Catholics and Protestants was an important step toward the goal of political coherency in Europe.
Meanwhile, by the 1540s Protestant churches had established their basic theological convictions. In 1530 Melanchthon finished editing the Augsburg Confession; John Calvin completed his first edition of his magnum opus, Institutes of the Christian Religion, in 1536. Moreover, doctrinal slogans such as sola fide (faith alone) had become familiar throughout Europe. All of this meant that Charles V’s dream of unification among Catholics and Protestants was no small feat.
This was a gathering of the Protestant intelligentsia; bright sparks from both sides were chosen to participate. On April 21, 1541, the Emperor announced their names. Philip Melanchthon, Martin Bucer, and Johann Pistorius represented the Protestants (a young John Calvin was present on the sideline). For the Roman Catholic Church were Johann Eck, Johann Gropper, and Julius Pflug. Cardinal Gasparo Contarini was papal legate, advising Catholic debaters behind the scenes. The theological meeting came to be called the Colloquy of Regensburg. 
To the surprise of many in attendance, theological discussion revealed a considerable amount of agreement. The first four articles, dealing with the creation of humans and their state before the fall; free will; the cause of sin; and original sin went uncontested and unchanged by both groups. 
On the next day, April 28, attention turned to the controversial matter of justification. Neither Eck nor Melanchthon was pleased with the “long-winded and highly ambiguous article.” Their insistence on its inadequacy led the group to set the book aside in favor of open discussion. After much debate and exchanging of further drafts, both sides managed to finally agree on May 2, when Protestants amended the Catholic version to their satisfaction. The Catholic side, in turn, gave their consent. Agreement on Article Five then became official. An inside look at a Protestant’s perspective on the Catholic concession is found in a personal letter of Calvin to his friend William Farel:
You will marvel when you read the copy of the article on justification . . . that our adversaries have conceded so much. For they have committed themselves to the essentials of what is our true teaching. Nothing is to be found in it which does not stand out in our writings.
With agreement on the doctrine of justification, discussion continued on May 3 on the subject of the Church and its authority. This is when tensions rose. Articles Six through Eight were accepted with little dispute. Then came Article Nine, which dealt with the authority of the Church.
Like previous statements, Article Nine was expressed in the most conciliatory terms. References to the teaching office of the Papacy were deliberately excluded. Nevertheless, it asserted that God’s Word was not only bound to Scripture but also to the dogmatic tradition of the Church. In response, Melanchthon asserted the doctrine of sola scriptura (Scripture alone), since elevating tradition to the place of Scripture would have meant betrayal of the evangelical cause. Since the issue was of fundamental importance to Roman Catholic teaching, both sides became stuck in a doctrinal impasse. Everyone in attendance recognized that the colloquy was in jeopardy of an irreparable conflict.
Count Fredrick of Palatinate proposed that the Protestant representatives submit their own statement as an alternative. “Like the original article, this Protestant draft was unpolemical, and went far to meet the Catholic position.” This statement acknowledged the interpretive role of the Church. And following Augustine they agreed that Scripture was to be properly understood in the Church. Nevertheless, the Protestant side objected that interpretation of Scripture was bound to a particular ecclesial office, such as the pope. They argued, “On historical, therefore, as well as theological grounds the infallibility of the Councils and of the early Church Fathers could not be accepted.”
Confronted by an unyielding stalemate, Granvelle intervened, calling for further discussions of Article Nine to be postponed to the end of the colloquy. Among onlookers it may have appeared that the meeting was progressing according to plan, but to participants the severity of the impasse was obvious.
When the issue of authority was evaded, the doom of the colloquy appeared certain. Although dialogue proceeded to address articles 10 to 17 on the sacraments, the predicament of Article Nine continued to loom overhead. Finally, when it came to the doctrine of the Eucharist, Contarini departed from his normal conciliatory manner and dogmatically insisted on the use of the term “transubstantiation.” Another debate ensued. Historian Michael McDuffee explains why Contarini probably changed his attitude so drastically:
Contarini “fast forwarded” failure’s arrival by demanding that the Lord’s elements must be understood in terms of transubstantiation. He probably did this to cover himself after the issue of authority made it clear that there would be no general agreement. . . . It is true no agreement over the nature of the real presence of Christ was reached, however, this was an anticlimactic conflict. Doctrinal differences receded in significance in comparison to the single most important question, “who has the authority to pronounce on matters of doctrine?” This remains the most important point of division between Catholicism and Protestantism today.
On May 29 the Colloquy of Regensburg ended, having lasted in total for about a month, while the imperial convention continued until July 29. After the convention concluded, Contarini traveled to the Italian city of Lucca to attend a summit between Emperor Charles V and Pope Paul III. Arriving for its start on September 7, Contarini found lodging at San Frediano, the monastery over which Peter Martyr Vermigli served as Prior. Vermigli’s contemporary biographer, Josiah Simler, indicates that during these days, “Martyr and Contarini held daily discussions about religion.” According to Simler, these discussions revolved around the Regensburg debate.
What does Contarini’s experience teach us about the fundamental difference between Roman Catholic and evangelical Protestant faith? In short, it illustrates the crucial issue of religious authority. When he was forced to choose between his evangelical understanding of the gospel and the authority of the Roman Catholic institution, Contarini submitted to the authority of Rome. Other Italian reformers such as Peter Martyr contrast this response by embracing a life of exile on account of the gospel. But Contarini was truly a Catholic, as demonstrated by his choice of the papacy over his own conscience. This remains the basic difference between Catholics and Protestants to the present.
 Felix Gilbert, History: Choice and Commitment (Cambridge: Harvard University Press, 1977), 252.
 William J. Bouwsma, Venice and the Defense of Republican Liberty (Los Angeles: University of California, 1984), 124.
 Jedin’s language of “Turmerlebnis” suggests a parallel with the conversion experience of Luther. See H. Jedin, “Ein Turmerlebnis des jungen Contarinis,” in Kirche des Glaubens-Kirche der Geschichte: Ausgewählte Aufsätze und Vorträge, ed. H. Jedin (Freiburg: B. Herder, 1966), 1:167-190.
 The colloquy also goes by the name “Ratisbon,” which is the city’s French name.
 Hans J. Hillerbrand ed. The Oxford Encylclopedia of the Reformation (New York: Oxford University Press, 1996), 377-378.
 Peter Matheson, Cardinal Contarini at Regensburg (Oxford: Oxford University Press, 1972), 105.
 Agreement between Catholics and Protestants on the doctrine of justification (Article Five) was indebted to the idea of twofold righteousness (duplex iustitia), the notion that conversion brings both inherent and imputed righteousness. Because the position taught that one should rely completely on the latter for divine acceptance (imputation), and not depend upon inherent righteousness for such forgiveness, it aligned with the teaching of the Protestant Reformers. In a few years time, however, the Council of Trent would adopt a position that differed greatly, insisting on inherent righteousness as the one formal cause of justification. For more on this see Anthony N. S. Lane “A Tale of Two Imperial Cities: Justification at Regensburg (1541) and Trent (1546-1547).” InJustification in Perspective: Historical Developments and Contemporary Challenges, edited by Bruce L. McCormack (Grand Rapids, MI: Baker Academic, 2006), 119-145.
 Matheson, Cardinal Contarini at Regensburg, 142.
 Ibid., 118.
 Michael McDuffee, interview by author, 11 December 2000, Chicago, IL, electronic mail.
 Heinz Mackensen, “The Diplomatic Role of Gasparo Cardinal Contarini at the Colloquy of Ratisbon of 1541,” Church History 27 (1958): 316.
 Elisabeth Gleason, Gasparo Contarini: Venice, Rome, and Reform (Berkeley: University of California Press, 1993), 259. Marvin W. Anderson, Peter Martyr, a Reformer in Exile (1542-1562): A Chronology of Biblical Writings in England & Europe (Nieuwkoop: De Graaf, 1975), 46.
 Philip McNair, Peter Martyr in Italy: An Anatomy of Apostasy (Oxford: Clarendon Press, 1967),233.
 Josias Simler, Life, Letters, and Sermons, trans. and ed. John Patrick Donnelly, The Peter Martyr Library 5 (Kirksville, MO: Thomas Jefferson University Press, 1999), 24-25.