During the first half century of development of the gothic
style, the triforium was tall
and slender, equivalent in height to the clerestory
and thus dividing the elevation in three nearly equal levels. In the course
of the 13th century, the triforium will become smaller and smaller, tending
to disappear as refinements in technology permit a more unified elevation
open to outside light.
The earliest gothic buildings show two competing types of elevation:
the three-story elevation, such as is found at Paris and Chartres, and
the four-story elevation, as at Noyon. With time, the three story type
became the norm, and builders ceased to use the four-story plan.