The Cathedral of the Assumption of Our Lady (in French: Cathédrale de l’Assomption de Notre-Dame), is a cathedral church of Catholic cult under the invocation of Our Lady in the city of Chartres, in the department of Eure and Loir, in France, about 80 km southwest of the capital, Paris. It is also the seat of the Diocese of Chartres, in the Archdiocese of Tours.
This cathedral marked a milestone in the development of Gothic and began a phase of fullness in the domain of technique and Gothic style, establishing a balance between the two. He is extremely influential in many later constructions that were based on his style and his numerous innovations, like the cathedrals of Reims and Amiens to which he served as a direct model.
The most important figure in the history of this diocese was Bishop Fulbert de Chartres, scholastic theologian recognized throughout Europe.
In 1979 it was declared a World Heritage Site by Unesco.