In the 13th century, King Louis IX continued the work of Abbot Suger. He had the upper part of the chevet of the Saint-Denis Basilica rebuilt. He also financed the enlargement of the transept to accommodate the tombs of the kings and queens of France. The king’s architects worked on the verticality with the help of engaged columns that form the link between the base, the openwork triforium, and the ribbed crossbeams of the nave. They are all in one piece and make the nave seem higher than it really is. This technique was widely used throughout the Middle Ages, and became widespread on the construction sites of the Gothic cathedrals.