Humanities › History & Culture Wars and Battles Throughout History A primer on the major wars that shaped the modern world Share Flipboard Email Print History & Culture Military History Battles & Wars Key Figures Arms & Weapons Naval Battles & Warships Aerial Battles & Aircraft Civil War French Revolution Vietnam War World War I World War II American History African American History African History Ancient History and Culture Asian History European History Genealogy Inventions Latin American History Medieval & Renaissance History The 20th Century Women's History View More By Kennedy Hickman Military and Naval History Expert M.A., History, University of Delaware M.S., Information and Library Science, Drexel University B.A., History and Political Science, Pennsylvania State University Kennedy Hickman is a historian, museum director, and curator who specializes in military and naval history. He has appeared on The History Channel as a featured expert. our editorial process Facebook Facebook Kennedy Hickman Updated November 07, 2020 Since the dawn of time, wars and battles have had a significant impact on the course of history. From the earliest battles in ancient Mesopotamia to today's wars in the Middle East, conflicts have had the power to shape and change our world. Over the centuries, combat has become increasingly more sophisticated. However, war's ability to change the world has stayed the same. Let's explore some of the biggest wars that left the greatest impact on history. 01 of 15 The Hundred Years' War The LIFE Picture Collection via Getty Images / Getty Images England and France fought the Hundred Years' War for over 100 years, from 1337 through 1453. It was a turning point in European battles that saw the end of valiant knights and the introduction of the English Longbow. This epic war began as Edward III (ruled 1327–1377) attempted to gain the French throne and reclaim England's lost territories. The years were filled with a multitude of smaller wars but ended with a French victory. Ultimately, Henry VI (r. 1399–1413) was forced to abandon English efforts in France and focus attention at home. His mental stability was called into question, leading to the Wars of the Roses just a few years later. 02 of 15 The Pequot War Bettmann Archive / Getty Images In the New World during the 17th century, battles were raging as colonists struggled against Indigenous peoples. One of the first was known as the Pequot War, which lasted two years, from 1636 through 1638. At the heart of this conflict, the Pequot and Mohegan tribes fought each other for political power and trading capabilities with the newcomers. The Dutch sided with the Pequots and the English with the Mohegans. It all ended with the Treaty of Hartford in 1638 and the English claiming victory. Hostilities on the continent were quelled until King Philip's War broke out in 1675. This, too, was a battle over Indigenous peoples' right to lands being inhabited by settlers. Both wars foreshadow the next two centuries of tenuous relations between non-Indigenous and Indigenous peoples. 03 of 15 The English Civil War Edward Gooch Collection / Getty Images The English Civil War was fought from 1642 through 1651. It was a conflict of power grabbing between King Charles I (r. 1625–1649) and Parliament. This struggle would shape the future of the country. It led to an early form of the balance between parliamentary government and the monarchy that remains in place today. Yet, this was not a single civil war. In total, three separate wars were declared during the nine-year period. Charles II (r. 1660–1658) ultimately returned to the throne with parliament's consent, of course. 04 of 15 The French and Indian War and The Seven Years' War PhotoQuest / Getty Images What began as the French and Indian War in 1754 between the British and French armies escalated into what many see as the first global war. Both sides garnered support from Indigenous tribes, including members of the Iroquois Confederacy for the British and the Wabanaki Confederacy for the French. It started as British colonies pushed west in North America. This brought them into the French-controlled territory and a great battle in the wilderness of the Allegheny Mountains ensued. Within two years, the conflicts made it to Europe and what is known as the Seven Years' War began. Before its end in 1763, the battles between French and English territories extended to Africa, India, and the Pacific as well. 05 of 15 The American Revolution Stock Montage / Getty Images Talk of independence in the American colonies had been brewing for some time. Yet, it was not until near the end of the French and Indian War that the fire was truly aflame. Officially, the American Revolution was fought from 1775 through 1783. It began with rebellion from the English crown. The official break-up came on July 4, 1776, with the adoption of the Declaration of Independence. The war ended with the Treaty of Paris in 1783, after years of battle all throughout the colonies. 06 of 15 The French Revolutionary and Napoleonic Wars Hulton Archive / Getty Images The French Revolution began in 1789 after famine, excess taxes, and a financial crisis hit the common people of France. Their overthrow of the monarchy in 1791 led to one of the most notorious wars in European history. It all began in 1792 with French troops invading Austria. From there, it spanned the globe and saw the rise of Napoleon Bonaparte (r. 1804–1814). The Napoleonic Wars began in 1803. By war's end in 1815, most of Europe had been involved in the conflict. It also resulted in America's first conflict known as the Quasi-War. Napoleon was defeated, King Louis XVIII (r. 1815–1824) was crowned in France, and new borders were drawn for European countries. In addition, England took over as the dominant world power. 07 of 15 The War of 1812 Interim Archives / Getty Images It did not take long after the American Revolution for the new country and England to find themselves in battle again. The War of 1812 did begin that year, though fighting lasted through 1815. This war had a number of causes, including trade disputes and the fact that British forces were supporting Indigenous peoples on the country's frontier. The new U.S. armies fought well and even attempted to invade parts of Canada. The short-fought war ended with no clear victor. Yet, it did much for the pride of the young country and certainly gave a boost to its national identity. 08 of 15 The Mexican-American War Smith Collection/Gado / Getty Images After fighting the Second Seminole War in Florida, American army officers were well-trained to handle their next conflict. It began when Texas gained independence from Mexico in 1836 and culminated with the U.S. annexation of the state in 1845. By early 1846, the first stage was set for battle and in May, U.S. President James K. Polk (served 1845–1849) asked for a declaration of war. The battles stretched beyond the Texas borders, reaching all the way to the California coast. In the end, the southern border of the United States was established with the Treaty of Guadalupe Hidalgo in 1848. With it came land that would soon become the states of California, Nevada, Texas, and Utah, as well as portions of Arizona, Colorado, New Mexico, and Wyoming. 09 of 15 The American Civil War Rischgitz / Getty Images The American Civil War would become known as one of the bloodiest and most divisive in history. At times, it literally pitted family members against each other as North and South fought hard battles. In total, over 600,000 soldiers were killed from both sides, more than in all other U.S. wars combined. The cause of the Civil War was the Confederate desire to secede from the Union. Behind this were many factors, including enslavement, state's rights, and political power. It was a conflict that had been brewing for years, and despite best efforts, it could not be prevented. War broke out in 1861 and battles raged until General Robert E. Lee (1807–1870) surrendered to General Ulysses S. Grant (1822–1885) at Appomattox in 1865. The United States was preserved, but the war left scars on the nation that would take quite some time to heal. 10 of 15 The Spanish-American War Corbis via Getty Images / Getty Images One of the shortest wars in American history, the Spanish-American War lasted only from April through August of 1898. It was fought over Cuba, because the U.S. thought Spain was treating this island nation unfairly. The other cause was the sinking of the USS Maine, and though many battles took place on land, the Americans claimed many victories at sea. The result of this brief conflict was American control over the Philippines and Guam. It was the first display of U.S. power in the wider world. 11 of 15 World War I Hulton Archive / Getty Images While the previous century had a good deal of conflict, no one could predict what the 20th century had in store. This became an era of global conflict and it started in 1914 with the outbreak of World War I. The assassination of Archduke Franz Ferdinand of Austria on June 28, 1914, led to this war that lasted through 1918. In the beginning, it was two alliances of three countries each pitted against one another. The Triple Entente included Britain, France, and Russia while the Central Powers included Germany, the Austro-Hungarian Empire, and the Ottoman Empire. By war's end, more countries, including the U.S., became involved. The fighting spanned and devastated most of Europe, and over 15 million people were killed. Yet, this was only the beginning. World War I set the stage for further tensions and one of the most devastating wars in history. 12 of 15 World War II Keystone / Getty Images It is hard to imagine the devastation that could take place in six short years. What would become known as World War II saw fighting on a scale like never before. As in the previous war, countries took sides and were divided into two groups. The Axis powers included Nazi Germany, Fascist Italy, and Japan. On the other side were the Allies, made up of Great Britain, France, Russia, China, and the United States. This war started due to numerous factors. A weakened global economy and the Great Depression, and Hitler and Mussolini's rise to power, were chief among them. The catalyst was Germany's invasion of Poland. World War II was truly a global war, touching every continent and country in some way. Most of the fighting occurred in Europe, Northern Africa, and Asia, with all of Europe taking the most devastating hits. Tragedies and atrocities were documented all over. Notably, the Holocaust alone resulted in over 11 million people killed, including 6 million Jewish people. Somewhere between 22 and 26 million men died in battle during the war. In the final act of the war, between 70,000 and 80,000 Japanese were killed when the U.S. dropped atomic bombs on Hiroshima and Nagasaki. 13 of 15 The Korean War Keystone / Getty Images From 1950 through 1953, the Korean peninsula was gripped in the Korean War. It involved the United States and South Korea backed by the United Nations against communist North Korea. The Korean War is seen by many as one of the numerous conflicts of the Cold War. It was during this time that the U.S. was attempting to halt the spread of communism and the division in Korea was a hotbed after the Russia–U.S. split of the country following World War II. 14 of 15 The Vietnam War The LIFE Picture Collection via Getty Images / Getty Images The French had fought in the Southeast Asian country of Vietnam during the 1950s. This left the country split in two with a communist government taking over the north. The stage is very similar to that of Korea just a decade earlier. When leader Ho Chi Minh (served 1945–1969) invaded the democratic South Vietnam in 1959, the U.S. sent aid to train the southern army. It was not long before the mission changed. By 1964, the U.S. forces were under attack by the North Vietnamese. This caused what is known as the "Americanization" of the war. President Lyndon Johnson (served 1963–1969) sent the first troops in 1965 and it escalated from there. The war ended with U.S. withdrawal in 1974 and the signing of a peace accord. By April 1975, the lone South Vietnamese army could not stop the "Fall of Saigon" and the North Vietnamese prevailed. 15 of 15 The Gulf War AFP via Getty Images / Getty Images Turmoil and conflict are nothing new in the Middle East, but when Iraq invaded Kuwait in 1990, the international community could not stand by. After failing to comply with U.N. demands to withdraw, the Iraqi government soon found out what the consequences would be. Operation Desert Shield saw a coalition of 34 countries send troops to the border of Saudi Arabia and Iraq. Organized by the U.S., a dramatic air campaign took place in January 1991 and ground forces followed. Though a ceasefire was declared shortly after, the conflicts did not stop. In 2003, another American-led coalition invaded Iraq. This conflict became known as the Iraq War and led to the overthrow of Saddam Hussein (served 1979–2003)'s government.