I want to know the answer to the following question:
In what year was Upper Alsace sold to the Archduke Sigismund?
All the background I'm provided with is that "The latter was able to use this tax and a dynastic marriage to his advantage to gain back full control of Upper Alsace (apart from the free towns, but including Belfort) in 1477 when it became part of the demesne of the Habsburg family, who were also rulers of the empire.". Is that enough to answer the question?
Answer: no