His father, Henry, Count of Württemberg, was mentally deranged,[2] likely as a result of his three-year imprisonment by Duke Charles the Bold of Burgundy,[citation needed] was banished to Hohenurach Castle in the County of Urach, and his only guardian died when he was nine years of age.In 1526 Philip had declared he was anxious to restore the exiled duke, and about the same time Francis I and Zwingli had intimated their willingness to assist in a general attack upon the Habsburgs.[4] In January of that year Francis I had definitely promised assistance; the Swabian League had just been dissolved; and, after a manifesto had been issued by Ulrich and Philip justifying the proposed undertaking, Württemberg was invaded in April 1534.In a few weeks Ulrich was restored, and in June 1534 a treaty was negotiated at Kaaden by which he was recognized as duke by Ferdinand, but was to hold Württemberg under Austrian suzerainty.By this treaty Charles, ignoring the desire of Ferdinand to depose Ulrich again, allowed him to retain his duchy, but stipulated that he should pay a large sum of money, surrender certain fortresses, and appear as a suppliant before the Emperor at Ulm.
Portrait of Duchess Sabina of Bavaria by
Barthel Beham
, 1530