This style from the 13th century canonized
proportions and shapes from early Gothic and developed them further in order
to achieve light yet tall majestic structures. The wall structure was
modified from 4 tiers to only 3 tiers - arcade, triforium and clerestorey.
Piers coronations made smaller in order not to stop the visual thrust
upwards. The clerestorey windows were changed from one window in each
segment, holed in the wall, to two windows united by a small rose window.
The rib vault changed from 6 ribs to 4 ribs. The flying buttresses became
mature and after they were embraced at Notre-Dame de Paris and Notre-Dame de
Chartres they became the canonical way to support high walls as they served
both structural and ornemental purposes.