Military engineering is the process of designing and building war machinery. It also includes developing the means to transport these war machines and to communicate between military sites. Inventors and engineers in ancient Greece and Rome created several impressive war machines. Sometimes, they improved on earlier devices, but they also invented new devices to solve particular problems encountered during wartime.
Much of ancient military technology involved producing devices to attack the defenses of a city during a siege*. The Greek historian Thucydides described one clever invention. In 424 B.C., the Boeotians mounted a siege against the city of Delium. The defenders of Delium had strengthened part of their city wall with wood. To attack this section of the wall, the Boeotians created a device that may have been the first flamethrower. They sawed a long pole in half lengthwise, cut a groove along each half, and then put the halves back together to form a long hollow pipe. From one end of the pipe they hung a kettle. They mounted the other end of the pipe on wagons and attached a leather bellows* to it. They then wheeled the pipe to the wooden section of the wall, poured burning charcoal and tar into the kettle, and worked the bellows. The blast of air from the bellows produced a great wall of flame that drove the defenders back and destroyed part of their defenses.
Besieging forces also used movable, fortified towers equipped with battering rams and other weapons to break down a city’s walls. In the late 300s B.C., a visiting engineer named Kallias told the people of Rhodes that he could defend the city with a crane that could lift off the ground any attacking siege tower, rendering the tower useless. The Rhodians were so impressed that they fired their military engineer, Diognetos, and hired Kallias.
* siege long and persistent effort to force a surrender by surrounding a fortress with armed troops, cutting it off from aid
* bellows an instrument that sucks in air on one side and blows it out forcefully on the other
This detail from Trajan’s Column depicts ancient soldiers building fortifications. In wartime, towers were fortified not just for defense but also for offense. Battering rams and weapons were often incorporated into these sturdy structures.
Soon, an enemy attacked Rhodes with a 160-ton siege tower that was 125 feet high and 60 feet wide. Only then did Kallias inform the dismayed Rhodians that he could not build a crane to handle this monstrous tower. The Rhodians begged Diognetos for help, and he came up with a simple but effective scheme. Working secretly at night, he made holes in the wall where the tower was expected to attack, sticking sloping wooden chutes through the holes. The entire population of Rhodes then poured mud, water, and sewage down these chutes. The next day, when the tower rolled forward, it bogged down in the muddy cesspool the Rhodians had created.
The most impressive military technology of the Greeks and Romans was the catapult—an instrument that hurled stones, arrows, or pointed shafts called bolts. The earliest such device was the crossbow, a handheld weapon that used a mechanism to draw back the bowstring on a heavy, stiff bow. The crossbow shot an arrow much farther and more forcefully than an ordinary bow. Military engineers developed new and more efficient kinds of crossbows during the 300s and 200s B.C. The largest known bow measured 15 feet from tip to tip and threw a 40-pound stone ball from a sling of leather or woven hair. Catapults used springs that consisted of a bundle of cords made from a flexible material to increase the amount of force created. At first, military engineers used cords made from plant fibers, but they later used the tissues of oxen or other animals. These cords were flexible and strong and could hold a great deal of tension.
Large catapults were not intended for use by individual soldiers. Teams of men positioned and operated them. Catapults that threw bolts were fairly accurate against targets up to 250 yards away, while those that hurled stones had a range of about 150 yards. With such devices, an army could attack oncoming soldiers, throw rocks over city walls to smash buildings and people on the other side, or hurl flaming arrows into a besieged city.
Some of the military engineering works built by the Romans still stand today. Across their empire, the Romans fortified their military towns with ramparts* and ditches. They built bridges and straight, interconnecting roads so that their troops could march quickly from town to town. During the Punic Wars with Carthage, Roman engineers also became skilled at building naval defenses, including harbors, lighthouses, and coastal forts, to guard themselves from invasion by sea. (See also Technology; Wars and Warfare, Greek; Wars and Warfare, Roman; Weapons and Armor.)
* rampart earth or stone embankment, often topped with a low wall, built to protect soldiers from enemy fire