Editing Martin Bucer (section)

==Doctrinal issues (1539–1542)==
At the end of 1538, shortly before the Catholic Duke [[Georg, Duke of Saxony|Georg of Saxony]] died, a religious [[Colloquy (religious)|colloquy]] was convened in [[Leipzig]] to discuss potential reforms within the Duchy. The [[Electorate of Saxony]] sent Melanchthon, and Philip of Hesse sent Bucer. The Duchy itself was represented by [[Georg Witzel]], a former Lutheran who had reconverted to Catholicism. In discussions from 2 to 7 January 1539, Bucer and Witzel agreed to defer controversial points of doctrine, but Melanchthon withdrew, feeling that doctrinal unity was a prerequisite of a reform plan. Bucer and Witzel agreed on fifteen articles covering various issues of church life. Bucer, however, made no doctrinal concessions: he remained silent on critical matters such as the mass and the papacy. His [[ecumenical]] approach provoked harsh criticism from other reformers.{{Sfn |Thompson|2004|pp=167–72}}{{Sfn |Greschat|2004|pp= 168–70}}

[[Image:Titian - Portrait of Charles V Seated - WGA22964.jpg|thumb|left|[[Charles V, Holy Roman Emperor|Charles V]] attempted to win back Protestant princes through a series of colloquies and imperial diets. When reconciliation failed, he sought to suppress Protestant resistance in the [[Schmalkaldic War]].]]
In the [[Treaty of Frankfurt (1539)|Truce of Frankfurt]] of 1539, Charles and the leaders of the Schmalkaldic League agreed on a major colloquy to settle all religious issues within the Empire. Bucer placed great hopes on this meeting: he believed it would be possible to convince most German Catholics to accept the doctrine of {{lang|la|[[sola fide]]}} as the basis for discussions on all other issues. Under various pseudonyms, he published tracts promoting a German national church.{{Sfn |Augustijn| 1994|pp= 107–19}}{{Sfn |Greschat| 2004|pp= 170–5}}  A conference in [[Haguenau]] began on 12 June 1540, but during a month's discussion the two sides failed to agree on a common starting point. They decided to reconvene in [[Worms, Germany|Worms]]. Melanchthon led the Protestants, with Bucer a major influence behind the scenes. When the colloquy again made no progress, the imperial chancellor, [[Nicholas Perrenot de Granvelle]], called for secret negotiations. Bucer then began working with [[Johannes Gropper]], a delegate of the archbishop of [[Electorate of Cologne|Cologne]], [[Hermann von Wied]]. Aware of the risks of such apparent collusion, he was determined to forge unity among the German churches.  The two agreed on twenty-three articles in which Bucer conceded some issues toward the Catholic position.  These included justification, the sacraments, and the organisation of the church. Four disputed issues were left undecided: veneration of the saints, [[Sine populo|private masses]], [[Sacrament of Penance (Catholic Church)|auricular confession]], and [[transubstantiation]]. The results were published in the "Worms Book", which they confidentially presented to a prince on each side of the religious divide: Philip of Hesse and [[Joachim II, Elector of Brandenburg]].{{Sfn |Matheson|1994|p=14}}{{Sfn |Eells|1931|pp = 271–87}}{{Sfn |Greschat|2004|pp=175–8}}{{Sfn |Thompson|2004|pp= 172–5}}

The Worms Book laid the groundwork for final negotiations at the [[Diet of Regensburg (1541)|Diet of Regensburg]] in 1541. Charles created a small committee, consisting of [[Johann Eck|Johannes Eck]], Gropper, and [[Julius Pflug]] on the Catholic side and Melanchthon, Bucer, and [[Johann Pistorius the Elder|Johann Pistorius]] on the Protestant side. The basis for discussion was the "Regensburg Book"—essentially the Worms Book with modifications by the [[papal legate]], [[Gasparo Contarini]], and other Catholic theologians. The two sides made a promising start, reaching agreement over the issue of justification by faith. But they could not agree on the teaching authority of the Church, the Protestants insisting it was the Bible, the Catholics the ''[[magisterium]]''—in other words, the pope and his bishops. Into the article on the mass and the Lord's Supper, Contarini had inserted the concept of transubstantiation, which was also unacceptable to the Protestants. As a result, the colloquy became deadlocked.  To salvage some of the agreements reached, Charles and Granvelle had the Regensburg Book reprinted with additional articles in which the Protestants were allowed to present their views. However, Luther in Wittenberg and the papal court in Rome had by this time seen the book, and they both publicly rejected the article on justification by faith.  The failure of the conference was a major setback for Bucer.{{Sfn |Eells|1931|pp=288–301}}{{Sfn |Greschat|2004|pp=179–82}}{{Sfn |Thompson|2004 | pp = 175–208}}

After Bucer's return from Regensburg, the city of Strasbourg was struck by the [[bubonic plague|plague]]. First, Bucer's friend and colleague Wolfgang Capito succumbed to the disease; then Bucer's wife Elisabeth died on 16 November 1541. How many children Elisabeth had borne is unknown; several died during child-birth or at a young age.{{Sfn |Eells|1931|pp= 417–8, 517}} One son, Nathanael, although mentally and physically handicapped, survived to adulthood and remained with the Bucer family throughout his life. During Elisabeth's final hours, she urged Bucer to marry Capito's widow, [[Wibrandis Rosenblatt]], after her death.{{Sfn |Selderhuis|1999|pp = 122–3}}  He married Rosenblatt on 16 April 1542, as her fourth husband—she had outlived Ludwig Keller, [[Johannes Oecolampadius]], and Wolfgang Capito.  She brought with her four children from her previous marriages. The new couple produced a daughter, whom they named Elisabeth.{{Sfn |Greschat|2004|pp=201–2}}