What was the Fourth Crusade?

The unusual connection between Venice and Byzantium

This article explores the complicated relationship between Venice and the Byzantine Empire. Venice grew up in the shadow of Byzantium, serving as a trade partner and faithful ally for centuries. Gradually, relations grew hostile, and Venetian ships would carry the Fourth Crusade to its fateful rendezvous with Constantinople. Visitors to San Marco can still see marble and porphyry from Constantinople, built into the walls of Venice’s preeminent church.

A map of the Byzantine Empire

This map, hosted on the World History Encyclopedia, shows the Byzantine Empire in four eras. The area shaded dark purple is the original Eastern Roman Empire. The light purple areas represent the conquests of Justinian. The dark purple line surrounds the middle Byzantine Empire. The hatched area, finally, indicates the small “Latin Empire” established after the Fourth Crusade.

Visualizing Byzantium in the year 1200

This is a computer reconstruction of the Byzantine capital at its apogee, just before the Fourth Crusade. Alongside detailed renderings of the Hippodrome and Hagia Sophia, it includes dozens of the imperial city’s less famous monuments, many of which can still be found in modern Istanbul. The reconstruction is a work in progress, and the Byzantium 1200 X account routinely posts updates.

Rise and fall of the Byzantine Empire in 60 seconds

In 330 CE, Emperor Constantine made the bold move of shifting the Roman capital to Byzantium and renaming it Constantinople. This decision helped shape the Eastern Roman Empire, or what we now call the Byzantine Empire. Here’s how the city rose to global prominence, and why its legacy lingers today.

The impressive walls of Constantinople

This video explores the land walls of Constantinople, built on the orders of Theodosius II in the mid-fifth century. They consisted of a triple line of defenses, studded with hundreds of towers and supplemented with a moat. The walls were besieged dozens of times, but were only broken in 1453 by the power of Ottoman cannons. As repaired by the Ottomans, the walls are still largely intact today.

The century-long debate over religious images in Byzantium

The iconoclast controversy, which tore Byzantium apart in the eighth and ninth centuries, centered on the use of sacred images (or icons) in Christian worship. The Iconoclasts (literally, “icon smashers”) regarded sacred images as sacrilegious; their opponents, the Iconophiles (“icon lovers”), defended icons as aids to personal devotion. After decades of struggle, the Iconophiles prevailed; their victory ensured that icons, and the brilliant mosaics inspired by them, remained a feature of Byzantine churches.

A medieval Italian visits Constantinople

In the tenth century, the Holy Roman Emperor Otto I sent Liudprand of Cremona, an Italian bishop, to Constantinople on a diplomatic mission. He was not successful. But the very undiplomatic report he sent back to the emperor about his experiences provides a unique – and often very entertaining – look at life and ceremony in the Byzantine capital, dramatically different from anything in Liudprand’s Italy.

The final war between the Persian and Byzantine empires

The Arab conquests of the seventh century, which swept over Egypt, Syria, and Mesopotamia, were made possible by a catastrophic generation-long war between the Byzantine and Persian Empires. That war, in turn, was the last act in a struggle that had gone on for centuries, and shaped the whole subsequent history of the Middle East.

The Knights Templar were the first officially recognized Christian military order

The Knights Templar sought to protect Christian pilgrims and expand their religion’s influence through might. The warrior monk organization formed after the First Crusade and were named after the fallen First Temple of King Solomon, out of which they were based—leading to the name “Templars.” This article describes the rise and fall of the monastic order.

Explore the medieval world in this 14th-Century map

This virtual replica of a 14th-Century map allows viewers to see the medieval world through a Christian framework. Jerusalem is the center axle of the map, harkening back to the Bible's Old Testament, which states Jerusalem is the "centre of...

Why did the Ottoman Empire violently target Armenians during WWI?

In anticipation of threatened Allied landings at the strategically important Gallipoli peninsula, Ottoman authorities arrested 240 Armenian leaders in Constantinople on April 24, 1915, and deported them east. This roundup is commemorated today by Armenians as the beginning of the genocide, according to this article.

Charlemagne sparked a medieval revival of learning and Roman culture

During the Carolingian Renaissance, Charlemagne—the king of the Franks and later the emperor of much of Western Europe—and his successors promoted education, the arts, and scholarship. Monasteries preserved hundreds of Roman texts, while architecture and artistic styles drew inspiration from classical Rome.

Stalingrad was the turning point of WWII in Eastern Europe

The six-month siege (July 1942–February 1943) ended when the Soviet Union’s counteroffensive, Operation Uranus, encircled and destroyed Germany’s 6th Army. This decisive victory shifted momentum permanently to the Soviets on the Eastern Front, marking a major strategic reversal in Europe and undermining Nazi Germany’s war capacity.

Hear how the Black Death reshaped Europe's economy

The Black Death killed tens of millions across Europe, but the labor shortages that followed shifted economic power. With fewer workers available, survivors demanded higher wages and better conditions—sparking what historians call a medieval “Golden Age of Labor.”

What happened during the 'harrowing of hell'

According to theologians, Jesus descended into the realm of the dead between his crucifixion and resurrection. He did this to liberate the "righteous" who died before him, including Adam and Eve. The belief draws on 1 Peter 3:18-20 and the Apostle's Creed phrase "he descended into hell," and is especially vivid in Eastern Orthodox theology and iconography.

Who was Ferdinand Magellan, and what did he do?

Portuguese explorer Ferdinand Magellan left Spain on a trip to gather spices and circumnavigate the globe with five ships, more than 250 men, outdated maps, and a profound misunderstanding of the Pacific Ocean's width. Hear from a historian on...

The Four Great Inventions are historically significant Chinese technological advancements

The inventions of paper, gunpowder, printing, and the compass advanced civilizations worldwide by spreading knowledge, enhancing warfare, and improving navigation.

Hear the story of Saint Nicholas, the inspiration for modern Santa Claus

A fourth-century Greek bishop in Turkey, Nicholas was known for his generosity and gift-giving. Legend holds that he secretly tossed gold bags through a window to save three sisters from slavery, which landed in stockings drying by the fire.

What was the longest year in history?

In 46 BCE, Julius Caesar declared the year would last 445 days. This four-minute podcast and accompanying article explain why. Caesar wanted to make the following year start after the winter solstice, an achievement attainable due to his tinkering with the Roman calendar. But to start the year right, Caesar had to stretch the transitional year, leading to the creation of Caesar's Year of Confusion, the longest year in history.

Volcanic activity may have triggered the Black Death by spewing gases that led to crop failures in Europe, thus forcing the import of grain ships with plague-infested fleas.

Spartacus: Enslaved ancient Roman gladiator turned revolt leader

Sold into slavery and forced to be a gladiator, Spartacus ultimately took the fight outside the arena and revolted against the Romans. This article dives into the history of the rebel leader. Spartacus was originally from Thrace, a part of ancient Europe that included parts of modern-day Bulgaria, Turkey, and Greece. Exactly what led to his enslavement is unclear, but it likely involved ancient Rome's attempt to subjugate Thrace.

What is Lent?

Lent is the 40-day period of fasting and penitence before Easter, modeled on Jesus's 40 days of fasting in the wilderness. Rooted in early Christian practice, it was formalized at the Council of Nicaea in 325 CE. Pope Gregory I established Ash Wednesday as its start in 601, creating the season's current structure of 46 days—40 fasting days plus six Sundays, which were traditionally treated as feast days.

Roosevelt's 4 elections were driven by 2 major crises

Franklin D. Roosevelt won third and fourth terms in 1940 and 1944 as Americans emerged from the Great Depression and sought continuity during World War II. Voters prioritized stability, keeping Roosevelt in office until his death in 1945.

Defining the use of 'Third World' in geopolitics

The term "Third World" is mostly out of use today for its limiting connotations, but in light of a reordering of geopolitical alliances amid the Ukraine war, historians are reevaluating the term's usefulness. Read the history of the term starting from the 1950s, and learn what several experts claim about its contemporary efficacy.

Exploring Kristallnacht

Nov. 9 and 10, 1938, saw Nazi members break into Jewish stores and homes across Germany in retaliation for the assassination of a German diplomat by a Polish Jew. The event—called "Kristallnacht," meaning "night of the broken glass"—was tacitly condoned by the German authorities at the time. This richly produced interactive explores the events of Kristallnacht guided by one of its survivors, Charlotte Knobloch.

Stanford built a Google Maps for the Roman Empire, revealing how much it cost to travel in the ancient world

Russia annexed Crimea after a disputed 2014 referendum

On March 16, 2014, a disputed referendum in Crimea reported overwhelming support for joining Russia. Moscow annexed the peninsula two days later, a move widely condemned as a violation of international law.

In 1963, a basement renovation in Turkey revealed a passageway to a hidden, multilevel underground city that once housed as many as 20,000 people

The Russia-Ukraine conflict is the largest ground war in Europe since World War II in terms of casualties, forces mobilized, and displacement of civilians.

The Dracula character, now seen as the vampire archetype, was inspired by a seafood-induced nightmare its creator experienced.

See photos of Meteora, a mountainous site in central Greece, home to 14th-century monasteries perched atop soaring outcroppings.

El Niño, Spanish for 'the boy,' was named after Jesus Christ because the phenomenon resembled the weather changes observed around Christmastime.

In 2019, a laptop loaded with six of the worst malware in history and described as 'an exhibit of historical weaponry' sold for $1.3M.

The US first hosted the World Cup in 1994, a tournament that lives in soccer infamy for its poor planning and the murder of Colombian player Andres Escobar, who'd accidentally scored on his own net.

Take a 3D tour of the Hajj, Islam's annual pilgrimage to Mecca, undertaken by over 1.5 million Muslims.

The term 'algorithm' originated from the Latinized name of al-Khwārizmī, a 9th-century mathematician whose works introduced Arabic numerals and the decimal-based numeral system to Europe and whose treatise 'Al-Jabr' gave algebra its name.

Search a massive database of over 4 decades of clues from the TV quiz show 'Jeopardy!'

Hotels in Cannes, the glamorous city on the French Riviera, hire hawks to ward off seagulls during the city's famous film festival.

The rivalry between Alexander Hamilton and Thomas Jefferson centered on federalism—the question of how much power the federal government should hold relative to the states.

The Mona Lisa's celebrity status and repeated restorations have obscured what made the painting so revolutionary for its time

According to the physics of black holes, our 4D reality may be a hologram—a projection of information coded on a 2D surface on the edge of the universe.

Hurricanes, which rely on air consistently spinning in the same direction, cannot cross the equator because air curves in opposite directions north and south of it.

The Brothers Grimm were lawyers before they were storytellers, but became interested in fairy tales as they began investigating how rules and customs had been passed down through cultures.

For centuries, Niagara Falls has been a magnet for daredevils seeking to conquer one of nature's most powerful wonders, with its 200-foot drop and water rushing at 32 feet per second with 280 tons of force.

The story of Dollree Mapp, whose legal challenge over her 1957 conviction for possessing "obscene material" led to a major strengthening of the Fourth Amendment

Legendary architect Frank Lloyd Wright designed the SC Johnson headquarters in Wisconsin, aiming to make a cathedral-like workplace

Abraham Lincoln was almost assassinated weeks before his inauguration as he traveled from Illinois to DC through Baltimore in 1861; it took two independent claims for Lincoln to be convinced the threat was real

Domino's Pizza's 30-minute delivery guarantee was responsible for the chain's 1980s surge, but it was discontinued after the company was found liable for delivery driver accidents.

Poison ivy's characteristic rash is caused by an allergic response to an oily compound in the plant called urushiol.

Doctors differentiate between a phobia and fear by asking patients whether their fear interferes with their day-to-day activities.