Thanks to lost paperwork, diplomatic technicalities, or just plain forgetting they had declared war in the first place, many countries remained in a state of war long after the actual fighting had stopped.
1. Roman Republic vs. Carthaginian Republic – 2,134 years
Cato the Elder before the Roman Senate. © Stefano Bianchetti/Corbis
After two Punic wars Rome decided they needed one more pass at Carthage. So in 149 BC, after rousing speeches in the Senate with Cato the Censor declaring unequivocally, “Carthage must be destroyed,” the Roman army set out once again to try to demolish the North African city state. While Rome was eventually victorious, the Carthaginians never actually surrendered, and the citizens fought the invaders long after they had breached the city walls.
In 1985, the mayors of modern Rome and Carthage decided to sign a ceremonial peace treaty as a sign of friendship, signing it among the ruins of the city the Romans had razed to the ground.
2. Taiwan vs. the Netherlands – 359 years
The Dutch arrived on the island we now call Taiwan in 1623. Originally it was a simple trading fort, but within a year the Dutch government had decided to try to Christianize the native tribes. Some converted and submitted to European rule peacefully, but others needed a little encouragement, which the Dutch generously provided by setting fire to their villages. By 1651, the Taromak tribe had had enough and took up arms against their oppressors; in response the Dutch declared war. The Dutch were eventually defeated by a Chinese army under the command of a man named Koxinga but no official peace was ever declared.
In 2010, Menno Goedhart, a representative for a Dutch trading company who had done much original research into the war after first learning about it in 2004, sought out the tribe’s current leader for an official end to the conflict. Goedhart, who was already an honorary member of the tribe, went to the village’s spirit hut and asked forgiveness and understanding from the ancestors. Goedhart, who is known locally as "Mr. Taiwan," retired in Xinhua Township shortly thereafter.
3. Scilly Islands vs. the Netherlands – 335 years
The Isles of Scilly are a small archipelago off the southwest corner of Britain. During the English Civil War they were a royalist stronghold after much of England had fallen to the republicans. In 1651, the Dutch, who were apparently really up for wars against small islands that year, allied themselves with Cromwell’s troops and declared war on Scilly. The royalists surrendered to the republicans shortly thereafter and the Dutch apparently forgot they had declared war at all.
In 1985, a Scilly historian wrote to the Dutch Embassy in London for definitive proof that the war was just a legend, and the Isles of Scilly were not still at war with the country. After some research, it was determined that the war was real, and still ongoing. The next year the Dutch ambassador to the United Kingdom came to the islands to sign an official peace treaty.
4. Huéscar vs. Denmark – 172 years
In the early 1800s, Napoleon was declaring war on just about everyone. The United Kingdom, Spain, and Portugal allied to try to defeat him, while Denmark supported France. In 1809, the Spanish municipality of Huéscar took it upon themselves to declare war on Denmark, and then promptly forgot about it.
In 1981, a local Spanish historian discovered the original declaration of war. A ceremony was arranged and on November 11 of that year the mayor of Huéscar and the Ambassador of Denmark officially ended their bloodless war. The town was apparently so enamored with their long-term adversaries that the next year they twinned with the Danish city of Kolding.
5. Berwick-upon-Tweed vs. Russia - 113 years
Berwick-upon-Tweed, a town on the border of England and Scotland, switched hands so many times that it was always named specifically on official documents. When the Crimean War started in 1853, the declaration of war included Berwick-upon-Tweed by name, but the peace treaty did not... meaning that, technically, this small town remained at war with Russia long after the war officially ended in 1856.
In 1966, a Soviet news reporter who had heard this tale came to Berwick and signed a peace treaty with the mayor, Robert Knox. Knox said, tongue firmly in cheek, "Please tell the Russian people through your newspaper that they can sleep peacefully in their beds." When international newspapers picked up the story, many reported that an actual Soviet official had done the signing, rather than a journalist.
6. Town Line, New York vs. United States - 84 years
According to local legend, the small township of Town Line voted to leave the Union in 1861 to become an enclave of the Confederacy. There is no surviving written record of the vote, and if it did happen there is no reason to believe it would have been legal. However, the story went national in 1945 and, true or not, pressure was put on the town to “officially” rejoin the United States. A reporter wrote to President Truman asking for advice on re-entry. The president responded, suggesting they serve veal at the celebration, “as a vehicle of peace.” The next year the town voted to rejoin the US, though it wasn't unanimous: 23 of the 113 voters wanted to stay with the Confederacy.
7. Montenegro vs. Japan – 101 years
During the Russo-Japanese war, the tiny country of Montenegro declared war on Japan in support of Russia. While mostly symbolic—considering they had no navy with which to actually fight Japan—some volunteers from the country did fight in the Russian army. When the war ended in 1905, Montenegro was left out of the peace treaty. This ceased to be a problem when the country lost its independence to Serbia in 1919.
But in 2006, when Montenegro again established itself as an autonomous country, it decided it was time to right this wrong. When the Japanese envoy arrived in the country to officially recognize it, he also carried a letter from the Prime Minister declaring the century-long state of war finally over.
8. Andorra vs. Germany – 25 years
While this tiny principality on the Spanish border declared war on Germany during WWI, no one thought to invite Andorran officials to the signing of the Treaty of Versailles. Although Andorra remained neutral during WWII, at the outset it was technically still at war with Germany, and remained so until 1939, when the mistake was corrected.
9. Costa Rica vs. Germany – 27 years
Unlike Andorra, everyone involved remembered that Costa Rica had declared war on Germany during WWI and should have been invited to the signing of the Treaty of Versailles. However, in Costa Rica’s case there was a bigger problem: the government under General Federico Tinoco Granados had taken power after a coup d'état the year before and was still unrecognized by most European powers. So the Costa Rica envoys were basically uninvited, leaving the country in a technical state of war against Germany until they were included in the Potsdam Agreement at the end of WWII.
10. Allies vs. Germany – 45 years
There is some argument that everyone involved in the war against Germany during WWII was still at war with them after 1945. Some historians assert that since Germany was immediately split into two countries after it fell to the Allied forces, no official treaty could exist until it was reunited in 1990. This was taken so seriously that, upon reunification four and a half decades after the official end of the war, the Treaty on the Final Settlement with Respect to Germany included provisions outlining that the war had indeed finally ended.
Even if you don’t buy that technicality, what definitely is true is that the United States was at war with Germany until at least 1951. While the Potsdam agreement was issued in 1945, the United States did not sign any sort of peace treaty for six years, partially because of stalling by the Soviet Union. So in 1951, the US formally ended the state of war, which took the legal place of an actual peace treaty.
11. North Korea vs. South Korea and the United States – 62 years and counting
In 1953 no one was in the mood to sign a peace treaty, but they were ready to stop fighting. The South Korean government was so angry it even refused to sign the armistice agreement that many consider the official end of the war. Instead it was signed by the US, the UN, and North Korea. However, a state of war still legally exists.
Since 2007 the idea of a peace treaty has been floated numerous times, with the leaders of the two Koreas meeting to try to come to terms. As recently as last year, North Korea asked the United States for an end to the war, saying that a peace treaty was the first step in international talks about the North disbanding their nuclear program. So far nothing has come of it though, and our countries remain at war.