The word Gothic began as an insult. The 16th century Renaissance critic Giorgio Vasari popularized it to link the style to the Goths who sacked Rome, while the medieval builders called their work opus Francigenum, French work, or opus modernum, modern work. Born in the Île de France around Paris in the 12th century, it replaced dark Romanesque barrel vaults and fortress walls with three upgrades: the pointed arch, the rib vault, and the flying buttress. Together they moved the load to the outside of the building and let the walls turn to glass. Abbot Suger fired the starting gun at the Abbey of Saint-Denis in the 1140s, convinced that radiant light was a physical form of divine beauty.

A vertical race followed. Chartres pushed its vault to 125 feet and Amiens past 140, until the choir vaults at Beauvais, reaching for 157 feet, collapsed in on themselves. The style then mutated by region: fan vaulting in England, Brick Gothic in the stoneless Baltic, and thick fresco walls in Italy, where Giotto and Cimabue painted the Basilica of Saint Francis at Assisi. Brunelleschi and the Renaissance buried it, and the 19th century Gothic Revival dug it back up for the Houses of Parliament, driven by nostalgia amid industrial smog and the Oxford Movement’s claim that Gothic was the only truly Christian style.

• Christopher Wren’s theory that the pointed arch came from Islamic architecture, and the Cluny Abbey arches that predate the First Crusade
• Why wind vibration and stress reversals, not just weight, brought down the vaults at Beauvais
• The tympanum over the doors as a stone billboard of the Last Judgment, with imagery set by church decree rather than the artist
• The Strix, a flesh-eating owl bat from Ovid’s poetry, and the difference between gargoyle water spouts and warning grotesques
• Gothic spreading to Flemish town halls, the Doge’s Palace in Venice, Oxford, and the Jagiellonian University in Krakow