A is for Arch: A-Z of Historic Buildings

A sophisticated Gothic arch in Brecon Cathedral, Wales. This one is ‘lobed’ or ‘cusped’, with two points projecting into the arch like teeth.

The word ‘architecture’ sounds like it should derive from the word ‘arch’, but it doesn’t. Architecture derives from Latin architectura and from Greek ἀρχιτέκτων, both meaning the practice of making and designing buildings. ‘Arch’ comes ultimately from the Latin arcus meaning ‘bow’, as in the weapon.

Nevertheless, arches are important in architecture. In fact, they’re one of the fundamental components of many buildings, though not all. What is an arch? Arches are curved openings. They can hold up weight above them, or they can simply hover in space as an ornament.

What’s interesting about arches from the point of view of a historian or heritage consultant is that they’re a kind of signature. From the early 19th century, historians of buildings have used arches to understand the date of building and their stylistic development over time. This began with the groundbreaking work by Thomas Rickman, called An Attempt to Discriminate the Styles of English Architecture, from the Conquest to the Reformation. The idea is simple: different time periods use different types of arches. The so-called Romanesque style, starting around the 11th century AD, used simple, semi-circular arches. They’re just called ‘round arches’.

Then, around the 1140s, a radical new architectural idea came into play, the Gothic. The principle behind all Gothic architecture is a type of arch: the ‘pointed arch’. This arch looks exactly as it sounds, rather like the end of a sword. Before historians settled on the name ‘Gothic’—a term to explore another time—some writers called the style the ‘pointed style’. You’ll find this term used in many works on architecture from the Victorian period.

Classical architecture, which was revived in the Renaissance and enjoyed dominance in Europe well into the 19th century, avoided the arch. True, there were many structures such as vast aqueducts which used the arch. But the underlying concept behind classical architecture is ‘primitive’: it seeks to take us backwards to the most basic kind of architecture. Arches, on the other hand, are quite sophisticated. What Classical architecture prefers is the ‘lintel’, spanning an opening with a rectangular stone, like a single Lego brick over a window or doorway. Flat stones would be placed atop vertical columns, linking one another to form a very simple structure.

You’ll find that when considerable weights were loaded onto structures, or huge spans were needed, even Classical architects had to use the arch for its strength. That strength comes from the special physical behaviour of an arch, which we’ll consider later on in this series.