Carthage was founded in the legendary age by Phoenician colonists from Tyre, the great trading city on the coast of modern Lebanon. The leader of the expedition was Dido, also called Elissa, the daughter of King Mutto and the sister of Pygmalion, who had murdered her husband Sychaeus, a priest of Melqart, to seize his gold. In a dream, Sychaeus appeared to Dido, revealed the hiding place of his treasure, and urged her to flee. She gathered her loyal followers, loaded the gold onto ships, and sailed westward, stopping at Kition in Cyprus to pick up a priest of Astarte and eighty young women dedicated to the goddess. They landed on the North African coast near the Gulf of Tunis and asked the local Berber chieftain Iarbas for land to settle.

Iarbas offered what he thought was a mocking bargain: as much land as a single oxhide would cover. Dido took the hide, had it cut into strips so thin they were almost thread, and knotted them end to end into one impossibly long cord. With this cord she encircled the entire hilltop of Byrsa, claiming every inch of ground within the circle as hers by right of the bargain. Iarbas, bound by his own word, had no choice but to honour the agreement. The hill became the citadel of the new city, which the Phoenicians called Qart-hadasht, the New City. While digging the foundations, the colonists uncovered an ox's head, an omen that the city would be wealthy but subject to others. They dug elsewhere and found a horse's head, an omen of power and warlikeness. Carthage was founded on this second spot, and from that day forward the horse became one of its sacred symbols.

The historical Carthage grew with extraordinary speed. The Phoenicians were the greatest traders of the ancient world, and Carthage inherited their commercial genius. It established colonies across the western Mediterranean, from Sicily and Sardinia to Spain and the Balearic Islands. Its navy was the most powerful on the seas, and its harbour at Carthage was an engineering marvel, capable of holding hundreds of warships in a circular basin hidden from enemy view. The city was governed by two annually elected suffetes, or judges, advised by a senate of elders and a council of one hundred and four members who oversaw the military. Its religion was Phoenician, centred on the worship of Baal Hammon and Tanit, the patron goddess whose crescent moon symbol became the emblem of the city.

But Carthage's greatest rival was Rome, and their conflict would define the history of the Mediterranean for more than a century. The First Punic War, fought from 264 to 241 BCE, began over control of Sicily and ended with Carthage's defeat and the loss of its island possessions. The Second Punic War, from 218 to 201 BCE, was the conflict that nearly destroyed Rome. Hannibal Barca, the Carthaginian general whose name means "grace of Baal," led an army of mercenaries and war elephants from Spain across the Alps into Italy. He won three crushing victories at the Trebia, Lake Trasimene, and Cannae, where he encircled and annihilated a Roman army of eighty thousand men. For sixteen years he ravaged Italy, but he could not take Rome itself. The Roman general Scipio Africanus invaded North Africa, forced Hannibal to return home, and defeated him at the Battle of Zama in 202 BCE. Carthage was reduced to a minor power, stripped of its empire, and burdened with a crushing indemnity.

The Third Punic War was not a war of survival but of extermination. Rome, paranoid and vengeful, demanded impossible concessions from the weakened city. When Carthage resisted, the Roman army besieged it for three years. In 146 BCE, the Roman general Scipio Aemilianus, the adopted grandson of Scipio Africanus, breached the walls and ordered the city destroyed. The inhabitants fought street by street, house by house, for six days. When the last resistance was crushed, the Romans burned Carthage to the ground, sold its surviving population into slavery, and, according to legend, sowed its fields with salt to ensure that nothing would ever grow there again. The city that had once rivalled Rome for mastery of the Mediterranean was erased from the map.

Yet Carthage was not gone forever. In 44 BCE, Julius Caesar planned to refound the city, and after his assassination, Augustus carried out the project in 29 BCE. Roman Carthage became the capital of the province of Africa Proconsularis, a thriving city of colonists and veterans that grew to be one of the largest cities in the Roman Empire. It produced the Christian theologian Tertullian and the martyr Perpetua, and its amphitheatre and baths were among the finest in North Africa. The Vandals captured it in 439 CE, the Byzantines recaptured it in 533 CE, and the Arab conquest of the 7th century finally ended its existence. Today, the ruins of ancient Carthage lie scattered across the suburbs of modern Tunis, a UNESCO World Heritage Site where tourists walk among the remains of Roman baths, Punic harbours, and the hill of Byrsa where Dido once cut her oxhide into strips.