Rayonnant was a very refined style of Gothic Architecture which appeared in France in the 13th century. It was the defining style of the High Gothic period, and is often described as the high point of French Gothic architecture. French architects turned their attention from building cathedrals of greater size and height towards bringing greater light into the cathedral interiors and adding more extensive decoration. The architects made the vertical columns and supports thinner, made extensive use of pinnacles and moldings. They combined the triforium gallery and the clerestory into single space and filled it with stained glass. They made extensive use of moldings and bar tracery to decorate the exteriors and interiors.
The most prominent features of the Rayonnant style were the enormous rose windows installed in the transepts and facades, made possible by the use of bar tracery. The design of the windows gave the name Rayonnant ("Radiant") to the style.