What Is the Longest War in History? The Real Answers, Ranked by Definition

The trivia answer is the 335 Years' War between the Netherlands and the Isles of Scilly, which supposedly ran from 1651 to 1986 without a single shot fired. The serious answers are shorter and messier: the Hundred Years' War (1337-1453, actually 116 years) if you want a single war that historians agree was a war, the Arauco War (roughly 1536-1818) if you accept a low-intensity colonial conflict, and the Reconquista (711-1492) or the Roman-Persian wars (roughly 54 BC to 628 AD) if you are willing to bundle centuries of separate campaigns under one name.

Which one is "the longest" depends entirely on what you are prepared to count as a war. A declaration with no fighting? A label invented by nineteenth-century historians for eight centuries of unrelated conflicts? An armistice that has held for seventy years without a peace treaty? Each definition produces a different record-holder, so this piece takes them one at a time and says which definition each answer relies on.

The 335 Years' War: a technicality with a good ending

The story goes like this. During the English Civil War, the Isles of Scilly, 28 miles off Cornwall, were one of the last Royalist strongholds. Royalist ships based there raided merchant shipping in the Western Approaches, including Dutch vessels — and the Dutch Republic had backed Parliament. In March 1651, Lieutenant-Admiral Maarten Tromp arrived off Scilly to demand reparations. Receiving none, he is said to have declared war on 30 March 1651, specifically on the Isles of Scilly rather than on England.

In June 1651, Parliamentary forces under Admiral Robert Blake took the islands. The Dutch fleet sailed home without engaging. No peace was made with Scilly, because as far as anyone in The Hague was concerned there was no longer anything to make peace with.

The story surfaced again in 1985, when Roy Duncan, a Scilly historian and council chairman, wrote to the Dutch embassy in London to have the legend debunked. Embassy staff looked into it, could not find a record of the war ever being ended, and the Dutch ambassador, Jonkheer Rein Huydecoper, flew to St Mary's to sign a peace on 17 April 1986 — 335 years after the supposed declaration. He remarked that it must have been alarming for the Scillonians to know the Dutch could have attacked at any moment. Casualties for the entire war: none.

It makes a much better story than it does a record. Several things undercut it. A declaration of war by a serving admiral against part of a country in the middle of that country's civil war is not obviously a declaration against a sovereign state, and the Isles of Scilly were never one. No contemporary Dutch declaration has been produced from the archives; the claim rests on later retellings. And the First Anglo-Dutch War, which broke out the following year, was formally ended by the Treaty of Westminster in 1654 — which would reasonably have settled any outstanding state of war between the Dutch Republic and English territory, Scilly included.

Treat it as folklore with an unusually well-documented ending, not as the longest war in history.

The Reconquista: 781 years, but probably not one war

If you count it as a single war, the Reconquista is the longest on anyone's list: from the Umayyad conquest of the Iberian peninsula beginning in 711 to the surrender of Granada to Ferdinand and Isabella on 2 January 1492. That is 781 years.

Most historians do not count it as a single war, and the reasons are not pedantic. For most of those eight centuries there was no continuous front, no continuous set of belligerents, and no shared war aim. Christian kingdoms — León, Castile, Aragon, Navarre, Portugal — spent a great deal of the period fighting each other. Muslim taifa kingdoms paid tribute, called parias, to Christian kings in exchange for protection against other Muslim rulers. Rodrigo Díaz de Vivar, El Cid, spent years in the service of the Muslim ruler of Zaragoza. Cross-confessional alliances were normal rather than scandalous.

The word "Reconquista" itself is the giveaway. It was not a medieval term for a medieval project; it became standard in the nineteenth century, when Spanish national historiography needed a story in which a single Christian Spain had spent 800 years recovering what was rightfully hers. Historians including Alejandro García-Sanjuán have argued at length that the framing distorts what actually happened. The fighting was real; the single war is a retrospective construction.

So: 781 years, on a definition most specialists reject.

The Hundred Years' War: 116 years and five English kings

The Hundred Years' War is the longest conflict that is routinely treated as one war by the people who study it, and even that is partly a matter of convenience. It ran from 1337, when Philip VI of France confiscated the English-held duchy of Aquitaine and Edward III responded by pressing his own claim to the French throne, to 1453, when the English lost the Battle of Castillon and with it everything in France except Calais. That is 116 years.

Five English kings ran it — Edward III, Richard II, Henry IV, Henry V and Henry VI — and five French ones, from Philip VI to Charles VII. Nobody who started it was alive to see it end.

What the name hides is how much of that century was not spent fighting. Historians usually split the war into three phases with long gaps between them: the Edwardian War (1337-1360), the Caroline War (1369-1389) and the Lancastrian War (1415-1453). The Treaty of Brétigny in 1360 produced the better part of a decade of formal peace. The Truce of Leulinghem in 1389 held, with interruptions, for roughly twenty-five years. Between the campaigns, English and French merchants traded and English and French monarchs negotiated marriages.

"Hundred Years' War" is also a nineteenth-century coinage, applied by French historians long after the fact to a sequence of related dynastic wars. It has stuck because, unlike the Reconquista, the phases genuinely share a cause, a dynastic dispute and a continuous set of belligerents.

The Arauco War: roughly 282 years in southern Chile

The longest colonial conflict, and the strongest candidate if you want a genuinely continuous war rather than a label, is the Arauco War: Spain, and later the Chilean republic, against the Mapuche of south-central Chile. It is usually dated from around 1536, when Diego de Almagro's expedition first clashed with Mapuche forces, to 1818 and Chilean independence — about 282 years.

The Mapuche were not conquered on the timetable Spain managed almost everywhere else in the Americas, for reasons worth understanding. Their society was decentralised, organised around local lineage groups rather than a single ruler, so there was no emperor to capture and no capital to take — the strategy that had brought down the Aztecs and the Inca simply had no target. They adopted horses and Spanish weapons quickly and adapted their tactics. The terrain south of the Bío Bío river, forested and heavily rivered, suited defenders. And Chile was the far periphery of the Spanish empire, chronically short of men and money.

The turning point was the Battle of Curalaba in 1598, where the Mapuche killed the governor, Martín García Óñez de Loyola, and then destroyed the Spanish cities south of the Bío Bío. After that, Spain largely gave up on conquest. The Parliament of Quillín in 1641 effectively recognised the Bío Bío as a frontier and the Mapuche as autonomous south of it. What followed was not three centuries of continuous battle but a long frontier of negotiated parliaments, trade, missionary activity and periodic raiding. Mapuche independence ended only with the Chilean occupation of Araucanía, 1861-1883.

Casualty figures for the whole period are not reliable and you should be sceptical of any specific number; the demographic catastrophe in the region owed at least as much to introduced disease as to fighting.

The Roman-Persian wars: about seven centuries of on and off

The longest-running rivalry, as opposed to the longest single war, was between Rome and Persia. It is conventionally dated from Crassus's invasion of Parthian territory in 54 BC — which ended in his destruction at Carrhae in 53 BC — to 628 AD, when the Byzantine-Sasanian War of 602-628 finally ended. That is roughly 681 years.

It cannot be one war, because the states involved changed underneath it. Rome went from republic to empire and then split, with the eastern half in Constantinople carrying the conflict from the fourth century onwards. Parthia was overthrown by the Sasanians in 224 AD. Between the campaigns there were genuine peaces, including a comparatively quiet fifth century after the partition of Armenia in 387.

The ending is the part most people miss. The final war, between Heraclius and Khosrow II, was catastrophic for both sides. Within about a decade of its conclusion, Arab armies out of the Arabian peninsula had taken Syria, Palestine and Egypt from an exhausted Byzantium and destroyed the Sasanian empire entirely. Seven centuries of stalemate were settled by a third party.

Other long conflicts worth knowing

The Eighty Years' War (1568-1648) — the Dutch Revolt against Spanish rule, ending with Spanish recognition of Dutch independence at the Peace of Münster. It contains its own long pause, the Twelve Years' Truce of 1609-1621.

The Thirty Years' War (1618-1648) — shorter, and far deadlier. Estimates of total deaths across central Europe generally run somewhere between 4.5 and 8 million, most from famine and disease rather than combat, with some German territories thought to have lost around a third of their population. These are estimates derived from patchy records and are argued over.

The "Second Hundred Years' War" (roughly 1689-1815) — a label coined by the historian J. R. Seeley in 1883 for the long Anglo-French struggle running from the Nine Years' War to Waterloo. It is a historiographical convenience, not a war anyone declared.

The Korean War (1950-present, in a sense) — fighting stopped with the armistice signed at Panmunjom on 27 July 1953, but no peace treaty has ever replaced it. South Korea was not a signatory. On that technicality the Korean War has been running for more than seventy years, which makes it the strongest live claimant to a long war on the "declared but not concluded" definition.

The shortest war in history

The counterpart record is much cleaner. The Anglo-Zanzibar War was fought on 27 August 1896 and lasted somewhere between 38 and 45 minutes, depending on which account you follow.

Sultan Hamad bin Thuwaini, who had cooperated with British interests, died on 25 August. His cousin Khalid bin Barghash took the palace without British approval. The British issued an ultimatum to stand down by 9am on 27 August. At around 9.02am, Royal Navy ships in the harbour began shelling the palace. The Sultan's flag came down around 9.40am, and Khalid escaped to the German consulate and eventually to German East Africa.

Casualties were extremely lopsided: contemporary British accounts put Zanzibari dead and wounded at roughly 500, against one wounded British sailor. Those figures come from the victors' reporting and should be read as an estimate.

Frequently Asked Questions

What is the longest war in history?

It depends on the definition. The 335 Years' War between the Netherlands and the Isles of Scilly (1651-1986) is the usual trivia answer, but it involved no fighting and probably no valid declaration; the longest conflict routinely accepted as a single war is the Hundred Years' War, at 116 years. If you accept broader groupings, the Reconquista spans 781 years and the Roman-Persian wars about 681.

What was the longest war the US has fought?

Afghanistan, from October 2001 to the withdrawal completed in August 2021 — just under twenty years. It overtook Vietnam, which is the previous answer on most datings and runs to roughly a decade of major US involvement, or about twenty years if measured from the first advisers in 1955.

What is the shortest war in history?

The Anglo-Zanzibar War of 27 August 1896, generally given as 38 to 45 minutes from the first naval shell to the surrender. The Royal Navy bombarded the Sultan's palace in Zanzibar Town after Khalid bin Barghash refused a British ultimatum to give up the throne.

Is the Korean War still technically ongoing?

Technically yes. Hostilities ended with an armistice in July 1953, not a peace treaty, and no treaty has been signed since — the 2018 Panmunjom Declaration committed both Koreas to pursuing a formal end but produced none. In legal terms the parties remain in a suspended state of war.

The takeaway

Most "longest war" answers are really arguments about categories. The 335 Years' War is a paperwork anomaly with a charming ceremony attached. The Reconquista is eight centuries of varied conflict wearing a nineteenth-century label. The Hundred Years' War is the most defensible single answer, and it lasted 116 years with long peaces inside it. Historical records tend to be like this once you look closely — the interesting part is usually the definition, not the number.

If that sort of thing appeals, why the Roman Empire fell covers another question where the famous date hides a much longer process, and 10 fascinating history stories has more of it in short form. Chunks publishes one free five-minute narrated history story every day on iOS and Android, to read or listen to.