Romanesque and Gothic

Between the year 1000 and the Reformation, the church was the great building of western Europe. Monasteries, cathedral chapters, bishops, kings and townspeople poured their wealth into it, and for five centuries the problem of how to build a large, lasting, fireproof and luminous house of God drove the most sustained run of structural invention before the industrial age. Historians divide the achievement in two. Romanesque, from about 1000 to about 1200, built with mass: thick walls, round arches, heavy vaults. Gothic, born near Paris in the 1140s and spreading across Europe over the next century, built with a skeleton: pointed arches, ribs and buttresses concentrating the loads so that the walls between could dissolve into glass. The two are not opposites. Gothic grew directly out of Romanesque, recombining elements that Romanesque builders had invented, and the masons who built both worked by the same methods of geometry and rule.

The Romanesque church

The Romanesque church is a basilica articulated. From the Early Christian churches of Rome it took the long nave, taller than the flanking aisles and lit by a clerestory above their roofs, and the apse at the east end. To that plan it added a transept crossing the nave in front of the sanctuary, so that the whole became a Latin cross, and it marked the crossing with a tower. At the west, the Carolingian westwork (a towered block with a chapel or gallery above the entrance) became a pair of towers flanking the façade, the ancestor of every twin-towered cathedral front.

℟The Latin cross: nave, aisles, transept, apse

Lay out the church as an Early Christian basilica (a tall nave lit from above, lower aisles on either side, a sanctuary ending in an apse to the east) and cross it with a transept, so that the plan becomes a Latin cross with a tower over the crossing.

Its first quality is mass. The walls are often one and a half to two metres thick, two faces of dressed stone enclosing a rubble core; windows are small and deeply splayed; the thrust of the vaults is taken by the sheer weight and width of the walls. Round arches, which rise half their span and push hard at their feet, suit this massive construction; they appear in arcades, windows, portals and the blind arcades that ornament the walls. The effect inside is grave and shadowy, the light falling in shafts from high narrow windows.

℟Mass resists thrust

Carry vaults on walls thick enough to absorb their thrust within their own mass; keep the windows small and set them low, below the springing of the vault, and strengthen the walls outside with shallow pilaster buttresses.

walls commonly 1½–2 m thick; buttresses shallow, window openings narrow and splayed

Within this mass Romanesque builders invented a new order. In Normandy and the Rhineland in the middle of the eleventh century they began to divide the nave wall into bays by shafts running from the floor to the roof, each bay containing one arch of the arcade and the windows above it. The pier became a compound pier, a core with half-columns on its faces, each half-column answering one of the arches it carries. Where one vault or one roof bay spanned two arches, the builders gave the main supports a heavier section and the intermediate ones a lighter one, the alternation of pier and column that gives Jumièges, Durham and Speyer their slow processional rhythm. At Hildesheim and Speyer the whole plan was laid out in squares, the crossing square repeated down the nave, each aisle bay a quarter of it.

Vaulting the Romanesque nave

Timber roofs burned, and a church that had lost its roof lost its treasures and often its relics. Stone vaults were the answer, but vaulting a tall nave was hard. The aisles were easy: low, narrow and square in each bay, they took groin vaults naturally. Over the nave, builders tried two strategies (see the chapter on vaults). In Burgundy and the south they built barrel vaults on transverse arches, accepting that the thrust must be resisted all along the walls and that windows must stay below the springing. In the churches on the pilgrimage roads to Santiago de Compostela (Conques, Toulouse, Santiago itself) the barrel was braced by galleries over the aisles, roofed with quadrant vaults leaning against the nave wall: an internal flying buttress.

In the Rhineland the imperial cathedral of Speyer was vaulted around 1080–1106 with great square groin vaults, each spanning two bays of the arcade, their thrust concentrated on the alternate piers. And at Durham, from 1093, the builders did something new: they vaulted the choir, and later the nave, with ribs (the first high rib vaults in Europe), and in the nave they used pointed transverse arches. Durham has everything Gothic would need except the will to use it for lightness.

Outside, the Romanesque church is a composition of stepped masses: the apse with its half-cone roof, smaller apses on the transepts, the lean-to roofs of the aisles, the tall nave, towers at the crossing and the west. The walls are articulated by shallow pilaster strips (lesenes) and friezes of little arches on corbels, the Lombard bands carried from northern Italy across Catalonia, Burgundy and the Rhine by travelling builders. Portals are deep and recessed in orders of round arches, and their tympana (at Moissac, Autun, Vézelay, Conques) carry the first monumental sculpture in the West since antiquity.

Saint-Denis and the new work

Between 1140 and 1144 Abbot Suger rebuilt the choir of the royal abbey of Saint-Denis, north of Paris. He wrote an account of the work, and what he valued is clear: light. His masons ringed the altar with an ambulatory and chapels so shallow that they merged into a single space, vaulted with ribs on slender columns, its outer wall almost entirely stained glass. None of the elements was new. The pointed arch came from Burgundy, the rib vault from Normandy and Durham, the ambulatory from the pilgrimage churches. What was new was their combination, and the aim to which it was turned.

℟Concentrate the loads; fill the rest with glass

Gather the weight and thrust of the vaults onto a few points by ribs, carry them down piers and out across the aisles by flying buttresses to external buttress piers, and the wall between the supports carries almost nothing, so it can be opened into windows.

The Gothic system rests on three devices, each an answer to the thrust of the vault. The pointed arch lets arches of any span rise to any chosen height, so that a vault over an oblong bay can close cleanly and the wall rib can frame a tall window (Pointed arches reach any height on any span). The rib vault gathers the weight and the thrust of the vault along its ribs onto a few points (the springers above the piers) and lets the webs between be thin and light (Ribs first, webs after). And from about 1180, starting probably at Notre-Dame de Paris, the flying buttress carries the concentrated thrust of the high vault out through the air, over the aisle roofs, to a massive buttress pier standing outside the aisle wall.

The flyer is a half-arch leaning against the clerestory wall at the level of the vault’s haunches, where its thrust is greatest; its foot rests on a buttress pier (the French culée) deep enough to carry the combined force safely to the ground. A heavy pinnacle on top of the pier adds weight that turns the resultant downward; the coping of the flyer often doubles as a gutter, throwing rainwater from the high roof out through a gargoyle. Once the thrusts are handled outside, the wall inside carries almost nothing. It can be opened up, first into large windows, then into a cage of glass.

The High Gothic bay

The cathedrals of the Île-de-France and Champagne refined the system in a single generation. Early Gothic churches such as Laon and Notre-Dame de Paris have four storeys (arcade, vaulted gallery, triforium and clerestory) and sexpartite vaults over double bays. At Chartres, rebuilt after a fire in 1194, the gallery was dropped, its structural role taken over by the flyers, and the elevation reduced to three storeys: a tall arcade, a low triforium passage in the thickness of the wall against the aisle roof, and a clerestory as tall as the arcade. Every bay was covered by a quadripartite vault on an oblong plan. This became the norm of High Gothic: Reims (begun 1211), Amiens (1220) and a hundred followers.

℟Arcade, triforium, clerestory

Divide the elevation of the nave into three storeys: a tall arcade opening into the aisles, a low triforium passage in the thickness of the wall against the aisle roof, and a clerestory of large windows reaching up into the vault.

Chartres: arcade ≈ clerestory, triforium a narrow band between

The piers themselves changed. At Chartres a round or octagonal core carries four attached shafts, one for each arch or rib that rises from it; the shaft facing the nave runs unbroken up the wall to the springing of the vault. The eye reads the whole bay as one frame of lines, from the base of the pier to the boss of the vault. The same period saw a race for height. Chartres rises about 37 m to its vault, Reims 38, Amiens 42; the choir of Beauvais, begun in 1225, reached about 48 m, and in 1284 part of its vault fell.

℟Ever taller, ever narrower

Within a generation the nave vaults of the French cathedrals rose from about 37 m to 48 m while their spans stayed near 15 m: the ratio of height to width climbed from about 2.3 to over 3, until at Beauvais part of the choir vault fell.

Chartres ≈ 37 m · Reims ≈ 38 m · Amiens ≈ 42 m · Beauvais ≈ 48 m

Seen whole, the High Gothic cathedral is a sequence of these bays, gathered into a cross and closed by the two great set-pieces of the design. At the east end the choir finishes in a semicircle of piers wrapped by an ambulatory and a ring of radiating chapels: the chevet, a cascade of roofs, flyers and pinnacles stepping down from the apse. At the west end rises the façade: three deep portals under gables, a rose window over the central door, a gallery of statues, and two towers that were rarely finished as planned.

℟The chevet: ambulatory and radiating chapels

End the choir in a semicircle of piers; wrap an aisle (the ambulatory) around it, and open a ring of chapels off the ambulatory, each with its own altar and windows, so that the east end steps down in tiers of roofs and buttresses.

Windows of stone and glass

As walls opened, the window became the principal field of Gothic design. The earliest large windows were plate tracery: separate openings (two lancets and a circle) cut through a slab of wall. In the radiating chapels of Reims, begun in 1211, the masons turned this inside out. The whole window arch was glazed and divided by thin moulded bars of stone that continued the mullions upward into sub-arches and a circle: bar tracery. Villard de Honnecourt, visiting the building site, drew one of these windows, and within a generation bar tracery had spread through France and England.

Geometric tracery, built of circles, foils and pointed sub-arches, dominated the thirteenth century; in the Rayonnant phase, from the 1230s, it spread over walls and triforium alike, until in the Sainte-Chapelle (consecrated 1248) the upper chapel is nearly all glass. The fourteenth century let the bars flow into the double curves of the ogee (Decorated in England, Flamboyant later in France), while English masons from the 1330s turned the other way, running the mullions straight up into the arch and crossing them with transoms: Perpendicular, the style of Gloucester choir and King’s College Chapel, with its gridded windows and fan vaults.

The rose window is tracery turned about a centre. Romanesque wheel windows had ringed a small oculus with colonnettes like spokes; the west rose of Chartres, of about 1215, is still a heavy plate pierced by circles; the transept roses of Notre-Dame de Paris, some forty years later, are almost all glass, their bars radiating from a hub through cusped heads to foiled oculi at the rim. A rose is designed by drawing one sector and rotating it; it is the purest example of the Gothic habit of generating the whole from one part by geometry.

℟The rose: a window turned about its centre

Design a rose by dividing the circle into equal sectors; fill each with the same traceried unit (a light with a cusped pointed head, an oculus above) radiating from a central hub, so that the whole is generated from one sector by rotation.

n petals · each sector 360° ⁄ n

The geometry of the lodges

The masters designed such buildings without scale drawings in the modern sense and without calculation. The written evidence of how they did it is scanty, because the lodges kept their methods to themselves, but what survives tells a consistent story. Design proceeded by construction. From a few given measures (the width of the choir, the side of a square) every other dimension was derived with compasses, square and cord, by operations that could be repeated full size on a tracing floor and checked by anyone who knew them.

The oldest witness is the portfolio of Villard de Honnecourt, some 33 leaves of drawings of about 1230. Among towers, roses and elevations of Laon, Chartres and Reims, it shows the masons’ geometry at work: figures of men and beasts set out on triangles and squares, and practical constructions, such as halving a square by drawing the square on its mid-points, the trick by which a cloister garth can be made equal to its walks.

℟Halve a square by turning a square within it

To make a square of half the area of another, join the mid-points of its sides: the rotated square so drawn has exactly half the area. Repeat to halve again.

side of inscribed square = s ⁄ √2 · area = ½ s²

Two and a half centuries later the same procedure appears in print. In 1486 Mathes Roriczer, master of works at Regensburg, published a booklet showing how to design a pinnacle “correctly”. From a single square he derives, by inscribing square within square, the widths of the body, its panels and its spire; he then raises the elevation, every height a multiple of the first side. Nothing is measured; everything follows. Lorenz Lechler, writing for his son in 1516, gives a similar system for a whole vaulted choir, with the width of the choir as the governing measure and the thickness of the wall a fixed fraction of it.

The fullest record of such reasoning is the argument over Milan Cathedral. Begun in 1386 on a five-aisled plan 96 braccia wide, the building needed a section, and the council that ran the works, unsure of its local masters, called in experts from the north. In 1391 the mathematician Gabriele Stornaloco worked out a section ad triangulum, fitted to an equilateral triangle on the width, and rounded its irrational height to 84 braccia so that it could be divided into six units of 14. In 1392 Heinrich Parler argued for ad quadratum, a section as high as it was wide. The council chose to build lower than either. In 1399–1401 the Parisian master Jean Mignot condemned the result as unsound, and when the Milanese answered that pointed arches do not push on their buttresses, he replied that art without science is nothing.

Ars sine scientia nihil est. (Art without science is nothing.)

We should not read Mignot’s scientia as structural science in the modern sense. He meant the geometrical rules of the craft: exactly the rules of Villard, Roriczer and Lechler. Modern analysis of masonry has shown why they worked: because masonry fails by losing its shape rather than by crushing, a rule of proportion that keeps a small building standing keeps a large one standing too. The masons’ geometry was a theory of stability, arrived at by experience and transmitted as design.

℟Art without science is nothing

A building’s form must follow the geometrical rules of the craft (scientia) as well as the experience of the builder (ars); neither is sufficient alone.

After the cathedrals

The great age of French cathedral building ended in the late thirteenth century, but Gothic did not. It spread with the Cistercians, the friars and the courts to Spain, Italy, Bohemia, Poland and Scandinavia; it built town halls in Flanders, colleges in England and hall churches in Germany, where nave and aisles rose to the same height under a single roof. Its vaults grew ever more elaborate: the tierceron, lierne and fan vaults of England (The fan vault: identical cones of tracery), the star and net vaults of Central Europe. Its tracery grew ever more fluid, until in the sixteenth century Gothic gave way, slowly and unevenly, to the Renaissance. Even then it never quite died: in England and northern Europe it lingered into the seventeenth century, and in the eighteenth and nineteenth it returned as the Gothic Revival, carried by the drawings and theories of Viollet-le-Duc, who read the whole style as a rational structure in which every form had its reason.