At the beginning of the 13th century, the classical Gothic style became widespread through its monumental elevation on three levels (large arcades, triforium and high windows) and the use of the buttress system to support the cathedral's central nave. The buttress was a great technical innovation, counteracting the forces of the central vessel and the nave; the high windows became even more vertical. From the 14th century onwards, Gothic style thrives, and every ornament and decoration are pushed to the limit.