Carinthia was the last German duchy to be held personally by the Emperor Henry III before he gave it to Welf. Welf III never married and had no children when he died at his castle on Lake Constance in 1055. He bequeathed his property to the monastery of Altdorf, where his mother was abbess. She in turn gave the property to Welf IV, the son of Welf III's sister Chuniza and Albert Azzo II, Margrave of Milan. Welf was the last of the Elder Welfs, his lands went to the senior branch of the House of Este, which is called the Younger House of Welf. His duchy went to Conrad III.