After the last remnants of the ancient regulations of the church of Hall had been abolished, his new rules appeared in 1543. Calls to
Leipzig in 1542, to
Tübingen in 1543, and to
Strasbourg in 1548 were declined in favor of his position at Hall. Brenz had long opposed the adherence of Hall and the margrave to the
Schmalkaldic League, since he regarded resistance to the temporal authorities as inadmissible. Gradually, however, his views changed, through the hostile attitude of the
emperor. In 1538 Hall entered the league, and after its defeat
Charles V came to the city (on 16 December 1546) and obtained possession of papers, letters, and sermons of Brenz, who, despite the bitter cold, was obliged to flee, although he returned on 4 January 1547. The new
Augsburg Interim of the emperor, which Brenz called
interitus ("ruin"), recalled him to the scene of action, and he earnestly opposed its adoption. The imperial chancellor,
Antoine Perrenot de Granvelle, demanded his surrender, and Brenz, warned by a note reading: "Flee, Brenz, quickly, more quickly, most quickly!" escaped on the evening of his forty-ninth birthday, 24 June 1548. He hastened to
Duke Ulrich, who concealed him in the castle of Hohenwittlingen near Urach, where, under the pseudonym of Joannes Witlingius, he prepared an exposition of Ps. xciii and cxxx. As the emperor was everywhere searching for him, Ulrich sent him by way of
Strasbourg to
Basel, where he was kindly received and found time to write an exposition of the prophecy of Isaiah. Duke Christopher called him to
Montbéliard, where, in January 1549, Brenz was notified of the death of his wife. The condition of his children induced him to go to
Swabia, but owing to the pursuit of the emperor, he was often in great danger, and the duke sheltered him in the castle of Hornberg near
Gutach. There he spent eighteen months under the name of Huldrich Engster (Encaustius), always active for the welfare of the Church, both by his advice to the duke and his theological labors. He declined calls to
Magdeburg,
Königsberg, and England. In August 1549 he ventured to go to Urach, where his friend Isenmann was now minister, in order to take counsel with the duke, his advisers, and
Matthaeus Alber, regarding the restoration of the evangelical divine service. In the autumn of 1550 he married his second wife Catherine, the oldest daughter of Isenmann. ==Activity, 1550–53==