However, the duke profited from his support of Charles V in the succession as Holy Roman Emperor, and in 1523 the Bishopric had to cede large territories to Wolfenbüttel.

When in 1542 Elector John Frederick I of Saxony and Landgrave Philip I of Hesse as members of the Protestant Schmalkaldic League came to the help of Goslar, they managed to occupy the complete Principality of Wolfenbüttel.

But in October he was captured by Hessian troops and kept prisoner,[1] until the Emperor finally defeated the Schmalkaldic League at the Battle of Mühlberg, freed Henry and reinstated him in 1547.

[2] Henry's affair with his mistress Eva von Trott (1506–1567), a lady-in-waiting to his consort Maria of Württemberg, produced ten children [1522-1558].

When rumours about his amour spread, he pretended she had died and arranged for a feigned funeral at Gandersheim Abbey, while she hid in Liebenburg Castle.