20 Times History Was Shaped by a Simple Personal Feud

Pompey’s jealousy of Caesar’s military fame had turned a close alliance into open enmity, and the Senate (acting primarily in Pompey’s interest) ordered Caesar to disband his army and return to Rome as a private citizen. Caesar’s response to this insult marked the end of the Roman Republic.

When Pope Clement VII refused to annul Henry’s marriage to Catherine of Aragon, Henry severed the Church of England’s ties with Rome and took it upon himself to grant the annulment. While the Reformation certainly drew on genuine theological currents, its starting point was a king who could not accept rejection.

In 328 B.C., Alexander the Great murdered his close friend and officer Cleitus the Black during a banquet, after Cleitus had implied that Alexander’s victories were due more to his father Philip than to himself. Alexander immediately pierced him with a spear, and the explosive temper he thus displayed destabilized his court until the end of his reign.

Great Britain declared war on Spain in 1739, partly because of a naval captain named Robert Jenkins, who had presented his severed ear to Parliament and claimed that a Spanish officer had torn it off eight years earlier. The “ear affair” was no longer a current issue, but it provided the war-hungry faction with exactly the pretext it needed.

When Napoleon discovered that his foreign minister, Talleyrand, was secretly providing intelligence to Austria and Russia, he publicly humiliated him but did not dismiss him. Keeping an enemy by his side out of pride deprived Napoleon of the diplomatic intelligence he needed just as his empire was beginning to fracture.

Achilles withdrew from the Trojan War not for strategic reasons, but because Agamemnon had seized his spoils of war, the campaign had reached a stalemate, and men were dying. The Iliad is, at its core, a very long reflection on what happens when the most powerful person in the story decides to act petty.

In 1960, Khrushchev reportedly banged his fist on the table at the United Nations General Assembly after a delegate accused the Soviet Union of imperialism. This gesture reinforced the West’s perception of Soviet unpredictability at a time when that perception directly influenced nuclear policy.

In 1804, Burr challenged Hamilton to a duel after Hamilton had made disparaging remarks about him. Burr shot and killed Hamilton, was charged with murder in two states, and America lost one of its most influential Founding Fathers as a result of a dispute over honor that had been brewing for years.

Stalin’s campaign against Trotsky was rooted in ideology, but its execution stemmed from a deeply personal grudge; he resented Trotsky for his intelligence and the condescension that accompanied it. Trotsky was expelled from the party, exiled, and finally assassinated in Mexico in 1940, thus bringing an end to a feud that had spanned two decades and two continents.

After the assassination of Franz Ferdinand, Austro-Hungarian officials saw this crisis as an opportunity to crush Serbian nationalism, which they already despised. The ultimatum issued to Serbia was drafted in such a way as to ensure its rejection, and the existing mutual contempt made any compromise impossible.

Privately, Arthur Wellesley harbored a hatred for Napoleon that went beyond mere military rivalry, and after Waterloo, this animosity led him to campaign relentlessly for Napoleon’s permanent exile rather than for a negotiated settlement. Napoleon was exiled to Saint Helena, an isolated island in the South Atlantic that had no strategic value other than being difficult to escape from, and died there six years later. 

Edison’s “War of the Currents” was portrayed as a debate over safety, but it was in reality a purely personal matter; he had publicly rejected alternating current, staked his reputation on direct current, and when Tesla—a former employee whom he had underestimated—proved him wrong, Edison responded by publicly electrocuting animals to make his point. He lost anyway.

Cato the Elder ended every speech he gave in the Senate—regardless of the subject—with the phrase “Carthage must be destroyed.” Rome had already defeated Carthage twice, but one senator’s obsession eventually became state policy, and in 146 B.C., Rome razed the city and sold the survivors into slavery.

When Tito refused to submit to Soviet authority in 1948, Stalin reportedly declared that all he had to do was “lift a finger” to bring Tito down. Tito responded by warning that if Stalin sent even one more assassin, he would send only one back; the resulting split divided the communist world and gave the West a considerable advantage in the Cold War.

The mutual hatred between Lyndon Johnson and Robert Kennedy was one of Washington’s worst-kept secrets. Johnson viewed Kennedy as a career politician who thought he could get away with anything; Kennedy saw Johnson as a crude and ruthless man. When their camps clashed in 1968, this animosity fractured the Democratic Party at a particularly critical moment.

In 1618, Protestant nobles from Bohemia threw three Catholic officials out of a window at Prague Castle—from a height of about 21 meters—to protest the Habsburgs’ religious policies. The officials survived by landing in a pile of manure; Catholics saw this as divine intervention, while Protestants mocked it, and the conflict escalated into the Thirty Years’ War.

Bismarck provoked France into declaring war in 1870 by altering a diplomatic telegram to make Prussia’s refusal of France’s demands seem more insulting than it actually was. He had correctly judged that Napoleon III’s pride would do the rest, and the German Empire was proclaimed in Versailles while the city was still under siege.

Henry II and Thomas Becket had been close friends before their falling out, and their constitutional conflict eventually escalated into an exhausting and personal feud. Henry’s outburst—“Is there no one to rid me of this troublesome priest?”—prompted four knights to assassinate Becket in his own cathedral, forcing Henry to do penance in public and irreversibly weakening royal authority over the Church.

The Duke of Marlborough did not lose his position as a result of a military failure, but because his wife, Sarah, had fallen out with Queen Anne over influence at court. As the political winds shifted, Marlborough was dismissed from his post in 1711, and this friendship that had turned sour disrupted the entire British approach to the ongoing war.

The failure of the Bay of Pigs in 1961 humiliated Kennedy, but its most dangerous consequence was the message Khrushchev took from it; he interpreted this mismanagement as a sign of weakness. This contempt, which intensified during their summit in Vienna that same year, directly contributed to his decision to deploy missiles in Cuba in 1962.