Today’s wars often last weeks, months, or even years. Concerned by the social and economic impact of casualties, the cost of weapons, and infrastructure destruction, most modern powers avoid open conflict unless it can be won quickly, cheaply, and with minimum bloodshed.
Some wars, however, have lasted decades or even centuries. These long wars usually consisted of a series of campaigns interrupted by truces or uneasy peace, as both sides rebuilt and prepared for the next inevitable conflict. What we consider full-blown wars today were once mere phases of much longer affairs.
As remarkable (and dreadful) as it sounds, it seems that an old Latin saying applies here: Si vis pacem, para bellum—“If you want peace, prepare for war.” The following eight conflicts consisted of some of the longest wars in history, making many of today’s engagements pale in comparison.
Duration: approximately 774 years
The Reconquista was possibly the most gargantuan campaign in military history, beginning with the Battle of Covadonga (in either 718 or 722 C.E.) and ending in 1492. The conflict was motivated by religious fervor, nationalism, and imperial ambition. Muslim forces, known as “Moors” to the Spaniards, had occupied most of the Iberian Peninsula (present-day Spain and Portugal) since the year 711. Christian rulers saw Muslims and Jews as enemies, and a series of wars called the Reconquista (Spanish for "reconquered") saw the Moors expelled from Iberia.
The dreaded Spanish Inquisition followed, in which Muslims and Jews were persecuted. In 1492, the city of Granada, the last Muslim stronghold, surrendered to Spanish forces. Having regained Spanish territory and captured ground from its former occupiers, Spain became a superpower. Portugal also acquired an empire, albeit a smaller one.
The Roman-Persian wars
Duration: approximately 681 years
The Roman-Persian Wars lasted an astonishing 681 years, during which time the Romans fought two successive Iranian empires, the Parthian Empire and the Sasanian Empire. The warfare began around 54 B.C.E., when Roman general Marcus Licinius Crassus led an invasion of Mesopotamia. Despite centuries of conflict, the empires were evenly matched and the borders of their respective territories barely changed over the years. Both sides also fought lengthy proxy wars, with allies often fighting on their behalf while the imperial states avoided direct warfare.
Conflict raged until 628 C.E., by which time the Roman Republic had evolved into the Roman Empire, and the eastern region became known as the Byzantine Empire. Meanwhile, the Parthian Empire had been subsumed by the Sasanian Empire. Fought over land and resources, the Roman-Persian Wars finally ended when the Persians were conquered by a new power, the Arab Muslim armies. The Byzantine Empire experienced huge territorial losses along with them.
The Germanic wars
Duration: approximately 588 years
Beginning with the Cimbrian War in 113 B.C.E., the Germanic wars raged for over half a millennium. They proved disastrous for the Western Roman Empire. The Germanic tribes had long been troublesome and rebellious, sparking conflicts that sapped Roman military strength, resources, and morale. Roman efforts to conquer Germania ended with the destruction of three entire legions and their support units in the Teutoburg Forest in 9 C.E.
A second series of uprisings and wars began in the fifth century under Western Roman Emperor Honorius. After centuries of conflict interspersed with uneasy truces, the drastically weakened Western Roman Empire collapsed in 476 C.E. The Germanic Wars had played a decisive role in the fall of the Western Roman Empire. Intermittent conflict with the Eastern Roman Empire (otherwise known as the Byzantine Empire) would continue for another century.
Duration: approximately 400 years
The Byzantine Empire fought various Arab caliphates over land, resources, and manpower, beginning with the Battle of Mu'tah in 629 C.E. and ending in the 11th century. In the 7th century, Muslim forces from Arabia rapidly conquered most of present-day Syria and Egypt, which had been part of the Byzantine Empire. The Byzantines later went on the offensive and re-gained much of their territory in the 10th century, exploiting caliphate fragmentation and the European Crusades to do so. After hundreds of years of conflict, both the Byzantine Empire and the Arabs were weakened and their fighting fizzled out. They were eventually both eclipsed by the rising Ottoman Empire.
The Ottoman wars
Duration: approximately 573 years
The Ottoman Empire engaged in almost-perpetual conflict as it rose to prominence. Defeating the Byzantines had earned the Ottomans imperial status, but in order to consolidate and expand, they needed new territory and resources outside their existing boundaries. Another series of wars fought in Europe between the 14th century and 1918 ended in their downfall.
The Ottoman Wars in Europe began in Bulgaria in 1345, saw several centuries of war against Venice (then a state in its own right), and expanded through present-day Southern and Eastern Europe, including multiple conflicts with imperial Russia. Ottoman power declined from the 19th century onward. The empire steadily lost territory and influence until it collapsed after the First World War. The Armistice of Mudros was signed in 1918 and the once-powerful Ottoman Empire eventually transformed into present-day Turkey.
The Philippines revolt
Duration: approximately 377 years
Spain’s imperial ambitions spawned another of history’s longest campaigns, that between indigenous Filipinos and Spanish colonists. In 1521, explorer Ferdinand Magellan claimed the Philippines for Spain. Magellan himself was an early casualty at the Battle of Mactan in 1521, a Spanish defeat which delayed colonization of the islands by several more decades.
In 1565, Miguel Lope de Legazpi arrived and began colonizing using divide and conquer tactics. Until the Philippine Revolution of 1898, indigenous people rebelled frequently against Spain. Spanish rule was never fully accepted by Filipinos, nor did they consent to their territory being renamed after King Philip II.
Several major rebellions were crushed by the Spanish. After centuries of periodic internal strife and international warfare, the Philippines finally declared independence in 1898, only to become an American colony when Spain ceded the territory after the Spanish-American War. Filipinos themselves were not consulted about being bartered from one empire to another, and, as one would expect, were widely dissatisfied with this centuries-long state of affairs.
The Mexican-Indian Wars
Duration: approximately 414 years
The war between the indigenous people of Mexico and their oppressors began with Spain’s invasion of the Aztec Empire in 1519. It largely ended with the Caste War of Yucatán, which was officially declared over in 1901, though skirmishes continued until 1933. All in all, the Spanish empire and colonists in present-day Mexico intermittently fought Native Americans for over four centuries. Tribal conflict and imperialism saw a series of wars, rebellions, and revolutions before the region finally settled along its current boundaries. However, the shadow of this war lingers and ethnic conflict is still prevalent in some regions, notably Chiapas, Mexico.