It began when Genoa became a self-governing commune within the imperial Kingdom of Italy, and ended when it was conquered by the French First Republic under Napoleon and replaced with the Ligurian Republic. Corsica was ceded to France in the Treaty of Versailles of 1768. The Ligurian Republic was annexed by the First French Empire in 1805; its restoration was briefly proclaimed in 1814 following the defeat of Napoleon, but it was ultimately annexed by the Kingdom of Sardinia in 1815.
Before 1100, Genoa emerged as an independent city-state, one of a number of Italian city-states during this period. Nominally, the Holy Roman Emperor was overlord and the Bishop of Genoa was president of the city; however, actual power was wielded by a number of "consuls" annually elected by popular assembly. Genoa was one of the so-called "Maritime Republics" (Repubbliche Marinare), along with Venice, Pisa, and Amalfi and trade, shipbuilding and banking helped support one of the largest and most powerful navies in the Mediterranean.
The Adorno, Campofregoso, and other smaller merchant families all fought for power in this Republic, as the power of the consuls allowed each family faction to gain wealth and power in the city. The Republic of Genoa extended over modern Liguria and Piedmont, Sardinia, Corsica, Nice and had practically complete control of the Tyrrhenian Sea. Through Genoese participation on the Crusades, Genoese colonies were established in the Middle East, in the Aegean, in Sicily and Northern Africa.
The collapse of the Crusader States was offset by Genoa’s alliance with the Byzantine Empire. As Venice's relations with the Byzantine Empire were temporarily disrupted by the Fourth Crusade and its aftermath, Genoa was able to improve its position. Genoa took advantage of this opportunity to expand into the Black Sea and Crimea. Internal feuds between the powerful families, the Grimaldi and Fieschi, the Doria, Spinola, and others caused much disruption, but in general the republic was run much as a business affair.
Between 1218–1220 Genoa was served by the Guelph podestà Rambertino Buvalelli, who probably introduced Occitan literature to the city, which was soon to boast such troubadours as Jacme Grils, Lanfranc Cigala, and Bonifaci Calvo. Genoa's political zenith came with its victory over the Republic of Pisa at the naval Battle of Meloria in 1284, and with a temporary victory over its rival, Venice, at the naval Battle of Curzola in 1298.