The attempt in the early 1540s by count Hermann von Wied to convert his electoral archbishopric to evangelical doctrines while retaining temporal lordship over his ecclesiastical principality (Hochstift) is a locus classicus of German Reformation history. This present study, meticulously based on wide archival research, does not seek to rewrite existing accounts; rather, it explores the context (Handlungsraum) within which both the archbishop and his opponents, the majority of the cathedral chapter, were able to act, and what political, legal and ecclesiastical strategies each adopted. In 1542 the archbishop invited Martin Bucer of Strasbourg to come to Cologne to draw up a blueprint for Reform. The resulting ‘Opinion’ (Bedenken) was not so much a church ordinance as a profession of faith or a catechism. It provided for communion in both kinds, worship in German, a ban on images (though some veneration of saints), but retained the seven sacraments. Luther was scornful. This halfway-house reflected von Wied's primary desire, which was to restore good order in the empire by means of a religious consensus, yet given his constitutional position, the proposals had obvious legal and political ramifications. He was faced, on the one hand, with a powerful aristocratic chapter, which invoked its hereditary right as a corporation under the Perpetual Territorial Accord (Erblandesvereinigung) of 1463 to release the lay Estates of the Hochstift from their oath of loyalty to the archbishop, should the latter act against the chapter's wishes. It is all the more remarkable, therefore that the Estates remained firmly behind von Wied to the bitter end; indeed, he enjoyed the support of a minority of the chapter, which separated itself from the majority and thereby threw the chapter's status as a unitary corporation into doubt. The imperial city of Cologne remained deliberately on the sidelines, but its university was unremittingly hostile to the archbishop. On the other hand, von Wied could not count on undivided support from members of the Schmalkaldic League, for landgrave Philipp of Hesse nurtured his own territorial ambitions in the north-west, while elector Johann Friedrich of Saxony had designs upon the duchy of Jülich-Cleves-Berg, where he hoped to succeed his brother-in-law, the ineffectual Wilhelm v. Landgrave Philipp was accordingly reluctant to countenance Wilhelm's admission to the league, the leaders of which indulged in gegenseitige Torpedierungsmassnahmen (Gabriele Haug-Moritz). Hermann von Wied continued to protest his loyalty to emperor Charles v while pursuing a two-pronged strategy of defence. Certainly he wished his cause to be declared a religious one under imperial law, and hence only resolvable by a general or national council of the Church; simultaneously, however, he invoked his ‘electoral pre-eminence’ under the imperial constitution to solicit support from other electors who might fear a derogation of their privileges. In this way he managed to bring the elector palatine Friedrich ii on board, who, despite his avowed ‘neutrality’, had in any case from 1545 permitted within his territory communion in both kinds, clerical marriage and the sacraments in German. The archbishop had no success, by contrast, with his colleagues in Mainz or Trier: the former had still to receive his pallium from Rome, while the latter lay sick and was likely to die. Emperor Charles v was anxious to avoid actions against Hermann von Wied which might unleash a civil war in Germany (at least until he felt militarily secure enough, which came with his defeat of the Schmalkaldic League at Mühlberg in 1547). Instead he invoked an obscure provision of the canon law, the principle of ‘notoriety’ – which had never been used in the empire before – to outlaw the archbishop (and which he then deployed against the rulers of Hesse and electoral Saxony). In the end the majority chapter of Cologne, flanked by imperial officials, and with imperial troops standing by, persuaded the lay Estates to renounce their loyalty and swear obedience to the coadjutor Adolf von Schauenburg as administrator of the archbishopric. Yet Hermann von Wied lived on for another five years, residing in the Hochstift, a striking testimony to the determination of all parties that religious conflict at the highest level should be resolved by judicial means within the framework of the empire as a legal-constitutional polity.