Thann is situated at the foot of the Vosges mountains, where the valley of the river Thur enters the Upper Rhine Plain.

Situated in the centre of the old town, the church known as the Collégiale is good example of the style of Gothic architecture that flourished in the Rhine valley in the late Middle Ages.

The building owes its name "La collégiale" to the college of monks who moved to Thann from the nearby town of Saint-Amarin in 1442.

For an extensive study of the Thann collegiate church, circumstances of its erection, issues of patronage, and unique sculptural programs, see Assaf Pinkus, Workshops and Patrons of St. Theobald in Thann (Waxmann Verlag: Muenster, Berlin, New York, 2006).

During demolition, one of towers overturned and cracked into sections, one of which forms a large stone ring known locally today as The Witch's Eye (L'œil de la sorcière).