6000-4000 BC Human activity begins in the area of Cagliari. Archaeological findings suggest that the territory has been continuously inhabited ever since.
7th century BC Phoenician colonists found Karalis.
5th century BC Carthage takes control of Cagliari and Sardinia.
238 BC Following the first Punic War, Sardinia becomes a Roman province. Cagliari soon becomes an important naval hub for fleets engaged in wars in Northern Africa.
456 The Vandals occupy Cagliari. In 474 they take control of the whole of Sardinia.
534 Sardinia is annexed by the Byzantine Empire which, over the following centuries, loses control of the island, leaving it in a state of anarchy.
10th-11th century Sardinia is divided in four autonomous realms, called giudicati: Arborea, Gallura, Torres and Cagliari. The Genoese and Pisan maritime republics establish a military presence and commercial activities along the Sardinian coast.
1258 The Pisans defeat the giudicato of Cagliari, destroying the capital Santa Igia and occupying the hill of present-day Castello, founding Castel di Castro.
1324 The arrival of the Aragonese marks the start of Spanish domination in Cagliari. Sardinia itself becomes a kingdom, governed by a viceroy, and its capital changes names to Càller.
1713 At the end of the War of the Spanish Succession, the Treaty of Utrecht assigns Sardinia to the Holy Roman Empire.
1720 Following the Treaty of The Hague, Victor Amadeus II, Duke of Savoy, is granted the title of King of Sardinia. The port of Cagliari and its position along the main Mediterranean commercial routes help restore the city's political and strategic importance.
1793 The French fleet lays siege to Cagliari, shelling the city and unsuccessfully attempting to land east of Poetto Beach.
1799-1814 During the Napoleonic Wars and the occupation of Piedmont, the Savoy family, who had been ousted from their court in Turin, resides in the Royal Palace in Cagliari.
1861 Sardinia becomes part of the unified Italian state. Cagliari gradually opens up to industrial and commercial investments, its old defense walls get pulled down, its urban landscape begins to be modernized with new architectural styles (Neo-Classical, Neo-Gothic and Art Nouveau) and places such as via Roma, Saint Remy Rampart and the annexed Indoor Promenade.
1943 Cagliari suffers heavy bombing by Allied air forces.
1948 Sardinia obtains the status of Autonomous Region and Cagliari is chosen as the seat of the local government and the regional assembly. In the following decades the city expands both inland and towards the sea, becoming what is now an urban continuum which includes Elmas, Assemini, Sestu, Monserrato, Selargius, Quartucciu and Quartu Sant'Elena, with a total population of around 350,000.