Fortifications

The development of new types of fortification during the Renaissance had far-reaching effects on military strategy and on political power. The new fortifications slowed down the pace of war by enabling cities to withstand attacks by gunpowder artillery and to use artillery in a defensive role. States on the offensive required large standing armies to carry out sieges and assaults against the fortifications. Supporting such armies may have contributed to the development of the centralized nation-state.

Evolution of Fortifications. Medieval* fortifications consisted of high walls and towers from which defenders shot missiles or dropped objects on attackers. The three traditional methods of attack against medieval walls all had distinct disadvantages. The first method, tunneling under the walls to collapse them from below ground, took a great deal of time. A second method, using battering rams to knock a hole in the wall, exposed attackers to arrows and stones from the defenders. The third method of attack involved building a wooden siege tower as high as the wall and moving it next to the fortification. However, siege towers could be damaged by fire or heavy stones hurled by catapults. Moreover, moving them into place required considerable effort and engineering work. These circumstances gave defenders the edge, and they could often hold out until help arrived or winter forced the attackers to leave.

The invention of mobile gunpowder artillery in the 1450s shifted the odds in favor of the attacker for a brief period. Cannons could easily punch through the high and relatively thin medieval walls. In addition, those defending the fortifications rarely used modern gun power because the older walls could not hold cannons. However, cities responded to the new weapons by making existing walls and towers lower and thicker. They also began to build platforms in front of the walls to hold defensive guns. Fortifications in northern and central Europe often added thick-walled towers specially designed for defense artillery.

The true revolution in fortifications occurred in Italy. Large, low gun platforms called bastions were built at the same height and thickness as the walls that connected them. This allowed defenders to mount heavy guns in the bastions and to move them quickly around on the walls as needed. Early bastions were circular, but by the late 1400s they assumed triangular or multisided pointed shapes. The pointed bastion eliminated the unavoidable blind spots of round towers and enabled defenders to shoot at attackers anywhere along the wall. Furthermore, the bastions and their connecting walls were set in deep ditches, making them lower and harder to hit. The pointed bastion was the key element in the new system of fortification, known as "the Italian trace."

The earliest pointed fortifications were not part of city walls but detached buildings defending city gates. They also appeared as "pillboxes" attached to the bases of round medieval towers. In the late 1400s some fortifications had round medieval towers combined with the newer thick, low walls and gun platforms. The first fortifications to include all the Renaissance elements were not built until the early 1500s. By the late 1500s bastions and their connecting walls had grown much larger and thicker, and they were set in wider ditches.

Complete Renaissance Systems. The first complete system of Renaissance fortifications was built in Italy between 1516 and 1520 at the papal* naval base of Civitavecchia. In 1544 Antwerp became the first northern European city with bastions around its entire city wall. During the Eighty Years' War between Spain and the Netherlands (1568–1648), both sides built bastions in many towns in the Low Countries*. Milan was the largest Italian city to be completely fortified by bastions, and various Mediterranean cities exposed to Turkish attack also rebuilt their defenses.

The best examples of complete Renaissance systems appeared in small or recently built towns because refortification presented difficulties in large, established cities. Rebuilding thicker walls around a city was extremely costly and often required taking over or destroying existing property. Some cities were simply too big to encircle with a new wall, which meant that sections of the city would remain unprotected. Plans for refortifying Rome collapsed in 1540 because of such problems. The size of the challenge is reflected by the fact that it took the city of Lucca over 100 years to complete its refortification.

A more practical solution to complete refortification was the construction of small citadels within the walls. In cities such as Paris and London, royal fortresses of this type provided defense and served as symbols of power. By the 1500s, the rulers of Italian city-states and cities began to build their own urban strongholds for the same reasons.

Some scholars suggest that the changes in warfare caused by the new fortifications changed the political organization of European countries. The new fortifications made it much harder to capture cities, allowing small powers to stand up to larger ones. In addition, states needed large standing armies to carry out long sieges. The planning and financing required to support such armies forced European governments to centralize and streamline their operations, leading to the rise of the nation-state during the 1600s.