Count Frederic II of Ferette constructed the Engelbourg Castle to guard the entrance to the Thur Valley. Completed in 1224, the castle stood for centuries. Its towers were crucial in defending the valley and protecting the people of Thann. 

In 1618, a massive religious war erupted between the Protestant and Catholic states of Europe. It became known historically as the Thirty Years’ War (1618 – 1648). Over the three decades of conflict, chaos, destruction, and famine, 8 million people including 20% of the German population had perished. The conflict didn’t bypass the Thur Valley and the King of France, Louis XIV, ordered the destruction of Engelbourg Castle in 1673. 

The castle’s walls were pulled down, its great halls burned, and the towers were toppled. All that was left standing was a mound of rubble, and one section of tower that remained to form the famous L’œil de la Sorcière, The Witch’s Eye.