This second volume of Wolfgang Capito's correspondence, covering 1524–31, documents his transformation from Erasmian humanist and crypto-Lutheran to openly Protestant leader. He became a major figure in the German Reformation, especially among those who favored the “sacramentarian” eucharistic doctrines of Huldrych Zwingli of Zürich over the more conservative eucharistic theology of Martin Luther. Although for a time after his move to Strasbourg in 1523 Capito maintained a cautious ambivalence, by January of 1524 he began to declare his support for the religious innovators openly. A letter of January 1524 (letter 174) to the humanist Willibald Pirckheimer flatly dismissed the claims of the Roman church; in April he helped draft a public appeal against the bishop's excommunication of several priests who had married; that same month he notified the city council that a local congregation had elected him as their parish priest and sought the council's approval, thus challenging the bishop's authority. In August 1524 he married the daughter of a city councilor and then defied a group of canons who tried to dismiss him because of his marriage.

Capito soon became the most prominent leader of the local Reformation, initially more influential than his colleague Martin Bucer. Capito and Bucer collaborated to support the eucharistic theology of Zwingli rather than the conservative one of Luther; yet they labored to heal the developing schism between Lutheran and Swiss reformers. The two men led the local clergy in urging the foundation of a local school (letter 311), they encouraged the council to establish control of the laity rather than the bishop over church appointments, and they repeatedly pressed the council to mandate the removal of religious images and to prohibit the celebration of masses. The council, religiously divided and concerned by the political consequences of drastic change, was slow to suppress traditional religious practices. Not until February 1529 did it finally prohibit the Mass. Both men attended the imperial Diet of Augsburg in 1530, and they collaborated in drafting the statement of doctrine that Strasbourg presented as an alternative to the Lutherans’ Augsburg Confession.

The correspondence also shows that Bucer gradually replaced Capito as the most influential leader of the Strasbourg Reformation. This change sprang from their differing personalities. Capito, though initially the leader, lacked the qualities that eventually made Bucer the outstanding spokesman of West German Protestantism. Capito was too mild, too tentative, perhaps too temperamentally skeptical. His rather mild reaction to the peasant rebellion in 1525 and his attitude toward the Anabaptists were viewed as weakness or even doctrinal unsoundness. Bucer, a far more assertive character, seemed more trustworthy. The correspondence reflects Capito's involvement in the great issues of the early Reformation. But it also provides insight into little events that shaped daily life, such as uncertainties involved in developing a married clergy and replacing episcopal control of the church by lay control, or the nagging personal quarrels and litigation caused by local religious conflict. There was constant uncertainty about the making of appointments, the apportionment of housing, the payment of salaries. As much as the great, or public, history of the period, these little crises reflect life in an age of religious upheaval.

Erika Rummel has produced a useful source for the life of an important leader of the Reformation. For the majority of the nearly three hundred letters in this volume — those for which the original text is already available in modern critical editions (such as the correspondence of Bucer) — this volume provides English-language summaries; but for letters surviving only in unpublished manuscripts or in inaccessible older publications, Rummel provides a full English translation. The original German or Latin text of such documents is available on the Capito project's website. This volume also includes six letters not available in time for volume 1. The appendices include four documents related to Capito's life in Strasbourg. The most interesting of these is an inventory of the Hebrew books in the library of the Strasbourg Academy, many of which probably came from Capito's personal library, for he was one of the most learned Hebraists of his time, author of a Hebrew grammar and two commentaries on Hebrew prophets.