An ancient town of the Ligures, Genoa flourished under Roman rule. Around the 10th cent. it became a free commune governed by consuls. Its maritime power increased steadily. Helped by Pisa, Genoa drove (11th cent.) the Arabs from Corsica and Sardinia. Rivalry over control of Sardinia resulted in long wars with Pisa; Genoa finally triumphed in the naval battle of Meloria (1284).
The Crusades brought Genoa great wealth, and the republic acquired possessions and trading privileges in areas from Spain to the Crimea. Genoa's expansion and its military defense were largely financed by a group of merchants who in 1408 organized a powerful bank, the Banco San Giorgio. Genoese policy in the eastern Mediterranean clashed with the ambitions of Venice, and long wars resulted, ending with the Peace of Turin (1381), which slightly favored Venice. Meanwhile, the Genoese republic was weakened by factional strife between Guelphs and Ghibellines, between nobles and the popular party. In 1339 the first doge (chief magistrate) for life was elected.
As Genoa gradually gained control of the cities of Liguria, it lost its outlying possessions. Rival factions in the city resorted to foreign aid. From the late 14th to the 16th cent., France and Milan in turn controlled the city, although nominal independence was preserved.
The power of Genoa was revived by the seaman and statesman Andrea Doria, who wrote a new constitution in 1528; the conspiracy (1547) of the Fieschi family against his dictatorship failed. Later the city came under Spanish, French, and Austrian control. The Austrians were expelled by a popular uprising in 1746, but in 1768 Genoa had to cede Corsica, its last outlying possession, to France. In 1797, French military pressure resulted in the end of aristocratic rule and the formation of the Ligurian Republic, which Napoleon I formally annexed to France in 1805. The Congress of Vienna united (1814) Genoa and Liguria with the kingdom of Sardinia. In 1922 a major European economic conference (see Genoa, Conference of) was held in the city.