It is often our mightiest projects that most obviously betray the degree of our insecurity. The construction of fortifications, for instance . . .—W. G. Sebald, Austerlitz (2001)

What is the peculiar appeal of military architecture? Whether Norman castle or Cold War concrete, there is a kind of sublimity that belongs to defensive design. It stems obviously from the massive scale of construction, and from the luxury of uncompromised execution that generous defence budgets afford. But there is also pleasure to be taken in the unornamented purity of style of structures that have been built solely for practical ends.

These qualities are abundant in the work of the seventeenth-century French military engineer Allain Manesson Mallet. Born in Paris in 1630, Manesson studied mathematics before becoming a soldier (he added the name Mallet in tribute to his teacher). In 1663, he was posted to Alentejo as an army engineer in the service of the Portuguese king Alfonso VI, where he fortified chateaux, until the Treaty of Lisbon in 1668. He returned to France with an appointment as mathematics instructor at the court of Louis XIV.

He recorded his military ideas in a highly successful manual, The Works of Mars (i.e. “the art of war”) in 1671. A year later came German and Dutch editions (the source of the images above), even though France was by then at war with the Netherlands.

Manesson’s book encompassed theories of fortifications from their origins in designs developed in the sixteenth century by Michelangelo and the architect Vincenzo Scamozzi, including more recent innovations of French and Dutch engineers. He included numerous “star forts” with four, five, six, seven, and nine points or bastions, as well as less regular structures designed to protect whole cities such as Lisbon. The perimeters were designed to eliminate blind spots and allow for firing outward at all angles from positions protected against attacking fire. Manesson even included diagrams showing how to generate the optimum angles of the bastions from a pure circle using geometry alone.

The strongly geometric structures had emerged as a response to the introduction of gunpowder-operated firepower, and drifted slowly north from Italian city states to the trading cities of northern Europe. The symmetry was formative in the planning of “ideal cities”, where the need for defence might have dissipated, but the geometric style was retained for aesthetic reasons.

The success of The Works of Mars depended greatly on the many fine engravings it contained. These were the work of the Dutch artist Romeyn de Hooghe, who lived for a time in Paris before settling in Amsterdam. A caricaturist, satirist, propagandist, pornographer, and spy as well as an illustrator and engraver, de Hooghe was one of the most remarkable characters in the artistic ferment of the Dutch “Golden Age”. Clues to the full range of de Hooghe’s technique are present in the graphic sketches that fill the margins of the technical designs — here an action-packed exchange of pistol fire, there a rolling perspective of a field of battle.

De Hooghe was a political cartoonist first of all, “the virtuoso of patriotic imagery”, according to historian Simon Schama. In 1667, for example, he produced a comic strip–like record of the signing of the Treaty of Breda ending the Second Anglo-Dutch War. Later, he revived the 1600s tradition of so-called “atrocity prints”, the propagandist cartoons that had once been used to vilify the Spanish, to rouse hatred against the new French enemy. His drawings showed the French playing football with Dutch heads and children being burned alive. In one of his most dramatic engravings, a dyke is breaking, with enemy soldiers, peasants, and horses and carts all suddenly washed away (six hundred were drowned in the incident) while the star fort of Coevorden, which he had painstakingly drawn in geometrical accuracy for Manesson’s book, squats in the background, powerless against the force of natural events.

In Amsterdam, de Hooghe ran a large studio producing posters, portraits, and pamphlets as well as illustrations for books of stories by everyone from Boccaccio to la Fontaine. He set up one of the first satirical magazines in Europe. Never shy of controversy, he made everything from diagrams for a self-defence manual to prints celebrating the art of necromancy. His pornographic drawings, including a volume titled “The Wandering Whore” illustrating sexual positions, earned him a conviction for blasphemy and indecency.

The crowning of the Dutch Prince of Orange as William III of England in the “Glorious Revolution” of 1688 yielded a graphic commemoration by de Hooghe of the Catholic king James II being deposed. Later, working as a spy, he exposed an Italian plan to destroy the dykes that protected Dutch cities from flooding. In 1706, he proclaimed the Dutch Republic the “freest and safest state” in the world . When he died two years later, his widow burned his erotic art to avoid any further trouble with the authorities.

De Hooghe’s fine draughtsmanship disguised one thing, however. Impregnable though they might look, the star forts made for obvious targets, and were vulnerable to sustained onslaught or siege, with no means of regroup or escape for those pinned behind their walls. Long after the concept had been metaphorically breached, military engineers continued nevertheless to design ever more ambitious forts, entranced perhaps by the symbolic ideality of the structures so apparent in the plan view of drawings such as de Hooghe’s. They were rendered obsolete for good with the advent of more powerful artillery in the nineteenth century.

Their legacy today is a series of highly visitable historic sites scattered throughout European countries and their former colonial outposts: Palmanova and Lucca in Italy, Berwick-upon-Tweed and Tilbury in Britain, Almeida in Portugal, Copenhagen, Fort George in Nova Scotia, Fort William in Kolkata, Zamość in Poland, Naarden in the Netherlands, Ticonderoga in New York State to name a few. These, and of course works of art, such as de Hooghe’s, and the numerous treatises on defensive architecture by Manesson, Jean Errard, and others. As W. G. Sebald writes: “No one today, said Austerlitz, has the faintest idea of the boundless amount of theoretical writings on the building of fortifications . . .”