Begun ca. 1225
A 7-bay ailsed nave is terminated to the west by a three-bay narthex and to the east by the crossing from which two-bay transept arms are generated. The three bays of the 5-aisled chevet lead to a five-segment hemicycle, an ambulatory and three radiating chapels -- the chevet plan recalls Rouen and Meaux Cathedrals as well as pre-Gothic Chartres. This is an ambitious architectural program, clearly inspired by cathedral prototypes.
The chevet has a three-story elevation: an arcade supported upon slender cylindrical columns, a skinny triforium and a very tall clerestory. In the hemicycle the clerestory windows have no tracery -- bar tracery appears in the chevet straight bays. The chevet-type elevation continues into the east side of the transept arms and west side of the north transept, but is transformed in the nave where the arcade is much taller and the triforium is omitted making a steep two-story elevation. The nave supports are a form of pilier cantonné with a bundle of shafts on the front surface.
Work on the chevet began c. 1220-25 and progressed quickly into the transept and nave (c. 1235). The construction of the western bays of the nave and narthex , however, was delayed until the 14th century
The Semur master as one who travelled and picked up motifs from elsewhere while at the same time establishing "Burgundian style." Importance of Auxerre as germinating field. Branner claimed that Semur nave 1230s was, with Nevers, amongst first Burgundian monuments to organize bays as total spatial units -- reception of Ile-de-France rayonnant
Henriot, M., "Les foires de Semur-en-Auxois," Annales de Bourgogne, 6, 1934 371-380
Truchis, P. de, "Semur-en-Auxois," Cong arch (Avallon) 74, 1907, 64-79