Genoa through the ages

The site has been inhabited since the fifth or fourth millennium BC. The first town, or oppidum, was founded in the fifth century BC, probably by the Ligures, on the hill now called Castello, and its inhabitants traded briskly enough to be reckoned the emporium of the Ligurians. The town held an equal pact, a foedus aequum, with Rome during the Second Punic War, and the Carthaginians destroyed it for that in 209 BC. Rebuilt, it received municipal rights after the Carthaginian wars ended in 146 BC and spread from the original castrum towards Santa Maria di Castello and the San Lorenzo promontory. Skins, timber and honey moved between the port and inland cities such as Tortona and Piacenza.

The Ostrogoths took the town after the fall of the Western Roman Empire, and after the Gothic War the Byzantines made it the seat of their vicar. When the Lombards invaded Italy in 568 Bishop Honoratus of Milan fled and held his seat here. For the next century and more Genoa was little more than a small centre, slowly building the merchant fleet that would become the leading commercial carrier of the western Mediterranean. In 934–35 a Fatimid fleet under Ya'qub ibn Ishaq al-Tamimi sacked and burned the town.

Genoa began to expand with the First Crusade, when it was a town of about 10,000 people. Twelve galleys, one ship and 1,200 soldiers sailed in July 1097 under the noblemen de Insula and Avvocato. The fleet carried and supplied the crusaders and blockaded Antioch during the siege of 1098, and at the siege of Jerusalem in 1099 Genoese crossbowmen under Guglielmo Embriaco fought as support units. Sea power turned into commercial treaties: Genoese merchants came to control a large share of the trade of the Byzantine Empire, Tripoli, the Principality of Antioch, Cilician Armenia and Egypt, though some territorial holdings were lost to Saladin's campaigns in Syria and Egypt late in the 12th century.

The rivalry with Venice ran through the 13th century. Venice's part in the Fourth Crusade had won it trading rights across the eastern Mediterranean and control of much of the region's maritime commerce, so Genoa allied with Michael VIII Palaiologos, emperor of Nicaea, who meant to restore the Byzantine Empire by retaking Constantinople. The treaty was signed at Nymphaeum in March 1261; on 25 July that year Nicaean troops under Alexios Strategopoulos recaptured the city, and the balance tipped to Genoa, which was granted free trading rights and then the greater part of Byzantine trading privileges, at Venetian and Pisan expense.

Chios, Lesbos and Smyrna became Genoese commercial stations, and in the same century the Republic took many settlements in Crimea, the territory known as Gazaria, where it founded the colony of Caffa. Victory over Pisa at the Battle of Meloria in 1284 lies behind the Doge's Palace, begun that year and made the doge's official residence in 1339. Corsica was formally annexed in 1347. During the Catalan–Genoese War the city itself was besieged and sacked by Guillem de Cervelló; in return for Genoese support of Aragonese rule in Sicily the Republic won free trading and export rights in the kingdom, and Genoese bankers lent to the island's new nobility.

The city's textile trade left a durable name. Around the 14th century Genoa was credited with the invention of blue jeans: its jean fabric was a fustian of medium quality and reasonable cost, close to the cotton corduroy for which the city was known, used for work clothes and issued to Genoese sailors, who needed cloth that could be worn wet or dry.

Two of the earliest banks in the world were founded here in the 15th century: the Bank of Saint George in 1407, which was the oldest state deposit bank in the world when it closed in 1805, and the Monte di Pietà in 1483. Christopher Columbus was born in Genoa around 1451 and gave a tenth of his income from the discovery of the Americas for Spain to the Bank of Saint George, to relieve taxation on goods. Aristocratic families (the Balbi, Doria, Grimaldi, Pallavicini and Serra among them) amassed great fortunes in the recovery that followed. Felipe Fernandez-Armesto and others have argued that practices Genoa developed in the Mediterranean, chattel slavery among them, were crucial to the exploration and exploitation of the New World.

Genoa then became something of an associate of the Spanish Empire, its bankers financing the Spanish crown's foreign ventures from counting houses in Seville and supplying the Habsburg system with fluid credit and dependable income; shipments of American silver were moved on from Seville to Genoa as capital for further ventures. Fernand Braudel called the years from 1557 to 1627 the age of the Genoese, a rule so discreet that historians long failed to notice it, while other historians stress that Genoese merchants and entrepreneurs settled across the empire and built networks that lasted into the 19th century. The city's trade still depended on control of the Mediterranean sea lanes, and the loss of Chios to the Ottoman Empire in 1566 struck a severe blow.

At the height of its power in the late 16th and early 17th centuries the ruling aristocracy financed a district of prestigious residences along new thoroughfares: the Strade Nuove, chief among them Via Garibaldi, Via Cairoli and Via Balbi. The houses were part of a public lodging system run through official registers, the Rolli: when a state visit fell due, a palace was drawn from the lists to host the visitor, its grandeur matched to his rank. Peter Paul Rubens compiled a book of drawings of these palaces and presented them as a model of living for the European nobility.

Decline set in from the 17th century. A French-Savoyard army briefly besieged the city in May 1625 and was seen off with Spanish help; plague killed as many as half the inhabitants in 1656–57; and in May 1684 the French bombarded Genoa for its support of Spain in the War of the Reunions. In 1729 the Corsicans rose against Genoese rule under Luiggi Giafferi and Giacinto Paoli, a struggle that cost the Republic dearly in money and men for 26 years and ended in a self-proclaimed Corsican Republic in 1755 under Giacinto's son Pasquale Paoli. The last Mediterranean colony, the island fortress of Tabarka, was lost to the Bey of Tunis in 1742.

Alarmed by the Convention of Turin of 1742, which allied Austria with the Kingdom of Sardinia, the Republic signed a secret treaty with France, Spain and Naples and declared war on Sardinia on 26 June 1745. The decision proved disastrous: Genoa surrendered to the Austrians in September 1746 and was occupied until a revolt freed the city two months later. Too weak to hold Corsica, the Republic ceded the island to France by the Treaty of Versailles in 1768, a year before Napoleon Bonaparte was born there.

Napoleon's invasion during the campaigns of 1796 brought down the Republic in early June the following year, overthrowing the elites who had ruled the state throughout its history; the Ligurian Republic was proclaimed on 14 June 1797 under French military occupation. During the siege of 1800, 30,000 of the city's 160,000 inhabitants died of starvation and disease. The Ligurian Republic was annexed by France in 1805 and divided into the départements of Apennins, Gênes and Montenotte.

After Napoleon's fall the city regained independence as the Repubblica genovese for less than a year before the Congress of Vienna handed the whole territory of the former Republic to the Kingdom of Sardinia under the House of Savoy, against the principle of restoring the legitimate governments of the old states. Genoa gave the Risorgimento the patriot Giuseppe Mazzini, who was born there.

Through the 19th century the city consolidated its position as a seaport and became an important steel and shipbuilding centre. Giovanni Ansaldo founded Gio. Ansaldo & C. in 1853, whose yards built many passenger ships; the ferry company Costa Crociere followed in 1854, the Registro Italiano Navale in 1861, and in 1881 the shipowner Raffaele Rubattino was among the founders of Navigazione Generale Italiana, later the Italian Line. Banca di Genova opened in 1870 and became Credito Italiano in 1895; Rinaldo Piaggio founded his locomotive and carriage works in 1884. By 1874 railways linked Genoa to Turin, Ventimiglia and Pisa, and so to France and the rest of Italy. From these berths ran the sea route from Genoa to New York, travelled in past centuries by millions of emigrants.

The city was bombarded in the Second World War: a replica of an unexploded British naval shell that struck the Cathedral of San Lorenzo stands inside it as a memorial. Steel was a major industry through the boom of the 1950s and 1960s and was phased out after the crisis of the late 1980s, as Italian production moved towards less polluting and more technologically advanced goods; shipbuilding (yacht construction and maintenance, cruise-liner building and military shipyards) stayed flourishing across the region. A serious flood in 1970 sent the Bisagno stream over its banks, and further floods in 2010, 2011 and 2014 led to work from 2015 to cover and channel the Bisagno and the Ferreggiano. In 1992 the Colombiadi marked the five hundredth anniversary of Columbus's crossing, and the old port was rebuilt and enlarged to designs by Renzo Piano.

Genoa hosted the 27th G8 summit in 2001; it was overshadowed by violent anti-globalisation protests in which one protester was killed. The European Union named the city European Capital of Culture for 2004 alongside Lille, and in 2006 the Strade Nuove and the system of the Palazzi dei Rolli were inscribed on the World Heritage List. On 14 August 2018 the Ponte Morandi road viaduct collapsed during a torrential downpour, killing 43 people; its remains were demolished in August 2019 and the replacement Genoa-Saint George Bridge, designed by Renzo Piano, was inaugurated in August 2020 during the COVID-19 pandemic.

Genoa is the capital of Liguria and seat of its metropolitan city, with some 565,000 inhabitants in 2025 and more than 1.5 million people in the wider metropolitan area along the Riviera. Its port is the busiest in Italy and in the Mediterranean. The city has the lowest birth rate and the oldest population of any large Italian city, the product of a long demographic decline that has slowed somewhat over the past decade.