Some historians claim that Mexico's victory at Puebla may have prevented France from arming the Confederacy

France invaded Mexico to install a puppet monarchy and recover debt

Napoleon III used Mexico's default on foreign loans as cover for a larger imperial ambition: overthrowing President Benito Juárez's government and installing a French-backed monarchy. The Mexican army's surprise victory at Puebla helped delay those plans by nearly a year.

Cinco de Mayo celebrates the Mexican victory at the Battle of Puebla

On May 5, 1862, Mexican forces under General Ignacio Zaragoza repelled a larger, more well-equipped French army at Puebla. The French endured roughly 500 deaths before retreating. Though the French ultimately captured Puebla a year later, the improbable one-day victory became a symbol of national pride.

Mexico’s political chaos weakened its defense against US invasion

Mexico’s post-independence instability—marked by coups, power struggles, and weak central control—left its northern frontier vulnerable. That political fragmentation shaped Mexico’s unpreparedness during the Mexican-American War and helped enable US conquest.

France, Spain, and Britain formed a joint military alliance to force Mexico to repay its debts

In October 1861, the three powers signed the Convention of London and landed troops at Veracruz that December. Britain and Spain reached settlements with Mexico and withdrew. France refused and aimed to change the regime in power in Mexico.

The US won every major battle of the Mexican-American War

Despite being outnumbered in key engagements, US forces defeated Mexican armies across every major front. Superior training, leadership, and logistics allowed the US to win decisively—capturing Mexico City without losing a single major battle.

Learn how Mexico’s anti-slavery stance shaped the US–Texas conflict

Historian Alice Baumgartner explores how Mexico’s abolition of slavery clashed with Anglo settlers' ambitions in Texas. The episode reveals how enslaved people fled south to freedom, reshaping the politics that led to Texas independence and the Mexican-American War.

Mexico admired Lincoln for opposing the war and supporting Mexican sovereignty

As a congressman, Abraham Lincoln condemned the Mexican-American War as unjust. Years later, as president, he backed Mexico’s fight against French occupation. His principled stance earned enduring respect and monuments across Mexico.

The Mexican-American War trained future Civil War generals

Many key military leaders of the Civil War—including Ulysses S. Grant, Robert E. Lee, and Thomas “Stonewall” Jackson—first saw combat in the Mexican-American War, gaining battlefield experience that shaped their later commands.

President Polk deliberately provoked war with Mexico

After Mexico refused to sell California and New Mexico, President James K. Polk ordered US troops into disputed territory between the Nueces River and the Rio Grande—knowing it would likely spark a conflict. When fighting broke out, he used it to justify declaring war.

American annexation of Texas eventually sparked war with Mexico

After Texas won independence from Mexico in 1836, the US annexed it in 1845—despite Mexico’s refusal to recognize Texas as separate. That annexation, combined with a heated border dispute, triggered the Mexican-American War the following year.

US military professionalism gave America a decisive edge in the war

The professionalism and engineering expertise of West Point–trained officers—like Grant, Lee, and Meade—gave the US a major advantage in the Mexican-American War, helping them win every major battle.

Support for slavery helped drive Texas to revolt against Mexico

Mexico abolished slavery in 1829, but many Anglo-American settlers in Texas brought enslaved people and refused to comply. Their desire to preserve slavery was a major factor in Texas’s 1836 rebellion and independence from Mexico.

Cinco de Mayo holiday celebrations originated with California's Mexican Americans during the Civil War

California Latinos first celebrated Cinco de Mayo in 1862 through patriotic assemblies called Juntas Patrióticas. Ardent Union supporters, these individuals saw the Puebla victory as a win for democracy against both French imperialism and the Confederate cause.

The Treaty of Guadalupe Hidalgo forced Mexico to surrender over half its territory

Signed in 1848, the Treaty of Guadalupe Hidalgo ended the war but came at a steep cost for Mexico—ceding 55% of its territory, including California and the Southwest, in exchange for $15 million and vague promises to protect Mexican residents.

Manifest destiny fueled US aggression against Mexico

The belief that the United States had a divine right to expand westward—known as manifest destiny—justified President Polk’s push for territorial conquest. It shaped public support for the Mexican-American War and framed the invasion as national destiny.

Irish immigrants deserted the US Army to fight for Mexico

During the Mexican-American War, hundreds of Irish Catholic immigrants—facing discrimination in the US Army—defected to Mexico and formed the Saint Patrick’s Battalion. Though many were captured and executed, they remain honored as heroes in Mexico.

How the US took half of Mexico

In just two years, the United States redrew the map of North America. Sparked by border disputes in Texas and fueled by President James Polk’s drive for expansion, the Mexican–American War (1846–1848) reshaped both nations.

According to Confederate leaders, the defense of slavery was the primary reason for secession.

New research challenges the myth that Montezuma peacefully surrendered to Spain

For centuries, historians claimed Montezuma II willingly ceded control to the conquistadors, and that later Aztec resistance was a rogue uprising. Evidence now shows no peaceful handover occurred, revealing a far more turbulent and contested encounter between the two warring empires.

Jefferson feared European control in the West of North America

Jefferson pushed for the Louisiana Purchase to prevent France or Spain from dominating the western frontier, securing control of the Mississippi River and vast lands that he felt were essential to America’s strategic and economic future.

Zachary Taylor became a national hero during the Mexican-American War

General Zachary Taylor led US forces to key victories in northern Mexico, earning widespread fame for his leadership. His popularity from the war propelled him to the presidency in 1848.

Puebla holds an annual battle reenactment on Cinco de Mayo

Each May 5, the city of Puebla marks the anniversary with festivals and a full military reenactment of the 1862 battle. While Cinco de Mayo is barely observed elsewhere in Mexico, it remains a ceremonial source of local pride in the state where the battle was actually fought.

The Union victory at Gettysburg marked a major turning point in the war

Fought July 1-3, 1863, the Battle of Gettysburg ended the Confederate invasion of the North. While the Union lost nearly 23,000 troops, its victory in one of America's most famous battles shifted the war's momentum decisively toward the North.

Abraham Lincoln's victory in 1860 sparked Southern secession—even before his inauguration

Abraham Lincoln's election on an antislavery expansion platform convinced many Southerners that their way of life was under threat. Within three months, seven states seceded from the Union—forming the Confederacy—before Lincoln took office in March 1861.

The Compromise of 1850 tried to settle disputes over land gained from Mexico

Territory acquired in the Mexican-American War reignited fierce debates over slavery’s expansion. The Compromise of 1850 aimed to ease tensions by admitting California as a free state and letting other territories decide the issue—but the compromise ultimately failed and helped pave the way to the Civil War.

The Continental Army invaded Canada in an attempt to seize Montreal and Quebec City in 1775.

See the path Spanish conquistadors took to conquer the Aztecs

Spanish expeditions reached central Mexico as the Aztec Empire was expanding its influence. After securing bases in the Caribbean, they advanced west into Aztec territory, triggering a cascading conflict depicted in this interactive map and timeline.

The Civil War introduced many technological advances to both society and warfare.

Hear about why Europe obeyed the Monroe Doctrine, despite American military weakness

This podcast explores the European background of the Monroe Doctrine, highlighting France's efforts to install aristocratic Bourbon monarchs in the newly independent Latin American republics—and how US opposition, British threats, and Spanish resistance ultimately disrupted those plans.

Madison urged Jefferson to accept the Louisiana Purchase despite constitutional concerns

As secretary of state, James Madison helped negotiate the 1803 Louisiana Purchase and persuaded Thomas Jefferson to proceed, arguing that the strategic and economic stakes outweighed the unresolved constitutional questions.

The Mexican-American War led to the birth of the Associated Press

To cover the distant war efficiently, rival New York newspapers pooled resources to share reports from the front—forming what became the Associated Press. The war marked a turning point in how Americans received real-time news about foreign conflicts.

US troops committed widespread atrocities during the Mexican-American War

American volunteer regiments frequently looted towns, raped civilians, and executed prisoners—especially in occupied northern Mexico. Historians have documented how racial hatred and impunity fueled war crimes that were rarely punished by military leadership.

Hear how the world reacted to the American Civil War

European nations closely watched the Civil War for its economic and political consequences. Some European nations quietly engaged diplomatically with the Confederacy but withheld recognition. When the Union made slavery's abolition a central cause, European public opinion turned sharply against the South.

The southbound Underground Railroad: finding freedom in Mexico

Until recently, the southbound Underground Railroad, as some scholars call it, has been largely overlooked, mainly because it left so few traces in surviving records. Read this article to learn more about this dangerous path and its travelers.

The British Royal Navy—not the US military—enforced the Monroe Doctrine for most of the 19th century

In the early to mid-1800s, the US lacked the ships and military power to prevent European nations from colonizing the Americas. Britain enforced this to protect its commercial interests by keeping rival European powers out of Latin America.

Hundreds of women secretly joined the Union and Confederate armies during the war

Hear the story of women who disguised themselves as men to enlist in both Union and Confederate armies—serving as soldiers, medics, and spies.

11 states formed the Confederacy, with 2 others claiming allegiance

Between December 1860 and June 1861, 11 Southern states officially seceded to form the Confederacy. Pro-Confederate factions in Missouri and Kentucky also declared secession, but both states remained largely under Union control throughout the war.

The final shots of the Civil War were fired in the Arctic over 2 months after the South's surrender.

The Aztec capital of Tenochtitlan fell after a brutal 75-day siege.

Future President Abraham Lincoln challenged Polk’s justification for war with Mexico

As a freshman congressman, Abraham Lincoln introduced the “Spot Resolutions,” demanding President Polk prove that Mexico had attacked on US soil. This constituted Lincoln’s first major political stand and highlighted growing dissent over the war.

A wave of Latin American independence movements most likely prompted the Monroe Doctrine

Between 1810 and 1822, many Latin American colonies separated from Spanish rule, 10 in the last two years. Concerns that Spain and its European allies might try to regain these republics were a main reason behind Monroe's declaration.

Most Confederate soldiers and leaders after the Civil War were pardoned

After surrender, most Confederate soldiers were pardoned and returned home, while leaders like Jefferson Davis faced short imprisonment. The South came under military occupation, Confederate money became worthless, and many former officers were barred from public office.

The Prize Cases established that the president can respond to an attack without waiting for Congress to act

When Lincoln blockaded Confederate ports at the start of the Civil War without congressional authorization, the Supreme Court upheld his actions, ruling that a president does not initiate war by responding to an attack and need not wait for Congress when the nation is already under threat.

The Louisiana Purchase nearly doubled America’s size in 1803

Acquired from France for $15M, the Louisiana Purchase added 828,000 square miles to the United States—stretching from the Mississippi River to the Rockies. US ambassadors in France signed the papers to buy the tract from the embattled Napoleon Bonaparte for a mere $15M before Jefferson learned the terms, due to the advantageous nature of the deal.

The Aztec Empire ruled over 80,000 square miles of central Mexico for nearly a century—until a small band of Spanish conquistadors brought it down in 1521.

Why Cinco de Mayo is more popular in the US than Mexico

Many in the United States believe Cinco de Mayo (celebrated annually on May 5) is Mexico's equivalent of the Fourth of July, but that's a common misconception: The holiday commemorates a battle in the fight for independence rather than the day Mexico declared independence. Interestingly, the holiday is more celebrated in the US than in Mexico, largely thanks to the Chicano Movement of the 1960s and 1970s.

The US finished what the French had started with Panama's canal

For about two decades, Suez Canal-builder and Frenchman Ferdinand de Lesseps led the project, but financial troubles forced it into the hands of the US, who completed it in 1914. This timeline, made to accompany the definitive PBS American Experience documentary about the canal, highlights major moments in its construction.

The diplomat who implemented Monroe's policy introduced the poinsettia to the United States

Joel Roberts Poinsett, appointed as the first US minister to Mexico in 1825 following the doctrine's announcement, took cuttings of a vibrant Mexican plant called the cuetlaxochitl during his time there. Americans loved the foliage and named it after him.

Champagne played a role in resisting the Nazis

When France surrendered to the Nazis in 1940, the invaders occupied the north. This was home to wine regions like Champagne and Bordeaux, which the Nazis were eager to loot. Winemakers took a stand by sheltering dissidents in their cellars, passing intelligence across borders, and even giving their lives to the cause.

Goya's 'The Second of May 1808' inspired Picasso's 'Guernica'

Goya’s painting commemorated Spanish resistance to Napoleon’s armies, making it a notable part of both the history of Spain and the romantic movement. But it took scholars over a century to realize the impact it had on Pablo Picasso, whose own anti-war work, “Guernica,” used Goya’s painting as a reference.