The city is located in the innermost part of the Gulf of Angels, at the S end of Sardinia, on the edge of the Campidano plain. It stretches between the sea, the Molentargius and Santa Gilla ponds and a group of steep and low limestone hills. It offers the safest and most comfortable port on the island.
In 238 BC, the sudden passage of Sardinia under Roman control took place, an indirect consequence of the Carthaginian defeat in the First Punic War. The Punic Krly then became Karales in Roman times.
Originally, the name of the city appeared in the singular form Karalis, testifying to the existence of a “vicus Karalis” created immediately after the conquest of Sardinia next to the pre-existing Punic city; the transition from the singular to the plural form Karales, to be placed during the second century BC, would attest to the successful merger of the two centers into a unified urban space.
From epigraphic sources there is no news of building initiatives that may have modified the urban layout of the city during the republican phase. The turning point for the construction history of Karales was marked by the attribution by Octavian of the statute of “Municipium Julium civium Romanorum” (around 38 BC) and the subsequent enrollment of Caralitan citizens to one of the tribes of Rome, the Quirina. The government of the city passed to a college of 'quattuorviri': two were in charge of the administration of justice ('IIIIviri iure dicundo') and also held the position of 'quinquennales', that is, of persons in charge of the census that took place every four years; two were in charge of taking care of the annona and public works ('IIIIviri aedilicia potestate').
Even in Roman times, as before in the Punic Age, the commercial vocation of the city and, consequently, the crucial importance of the port for the economic life of the urban center remained marked.
During the imperial phase, the city experienced an important urban development. It is during this period that the construction of public buildings and private homes takes place in various areas.
The city's acropolis must have been located between today's Castle and the upper part of the current Stampace district, located at the foot of the Castle. The current district of S. Avendrace was supposed to constitute the area of residence of the highest classes, as evidenced by the archaeological evidence of the so-called “Villa di Tigellio”. On the other hand, families from the less well-off class had to live between today's Corso Vittorio Emanuele and the port. Other stately homes were built on the slopes of the Bonaria hill.
The forum was located in today's Piazza del Carmine. A thermal building dating back to the 2nd century AD has instead been identified in Largo Carlo Felice and other traces of impressive thermal baths have been highlighted in Viale Trieste.
In Via Malta, where the Palazzo delle Poste is now located, an important late-republican “tempie-theater” came to light.
The necropolises have been located in different areas: Sant'Avendrace, Bonaria; Viale Regina Margherita (here the classiaries of the Miseno fleet department, which for a long period was based in the port of Cagliari, were buried).
In Viale Frà Ignazio, the amphitheater dating back to the 2nd century AD is still visible.
An aqueduct carried water from Siliqua through Decimo, Assemini, Elmas, reaching the city through today's Stampace district.
Several landings had to characterize the Roman city, however, pivoting around the area occupied by the current port.

History of excavations
Cagliari was affected by excavation interventions on several occasions, as early as the sixteenth century. However, investigations became more scientifically accurate and systematic in the nineteenth century, thanks mainly to the intense research activity carried out by Canon Giovanni Spano (1803-1882). Later, the investigations carried out by the archaeologist Antonio Taramelli (1868-1939) were also important. During the twentieth century, excavation interventions, carried out by the Superintendence for Archaeological Heritage for the Provinces of Cagliari and Oristano, multiplied, especially in conjunction with the urban development that affected the city.

Bibliography
P. Meloni, Roman Sardinia, Sassari, Chiarella, 1990;
S. Angiolillo, The Art of Roman Sardinia, Milan, Jaca Book, 1998;
A. M. Colavitti - C. Tronchetti, Archaeological Guide to Cagliari. Sassari, C. Delfino, 2003 (Archaeological Sardinia. Guides and itineraries; 31);
A.M. Colavitti, Cagliari, Rome, L'Erma di Bretschneider, 2003;
A. Stiglitz, “The Punic City in Sardinia: a reinterpretation”, in Aristeo. Notebooks of the Department of Archaeological and Historic-Artistic Sciences, 1, 2004, pp. 57-111;
M.A. Ibba, “Note on the archaeological, epigraphic and hagiographic evidence of the areas of worship of Karalì Punic and Roman Carales”, in Aristeo. Notebooks of the Department of Archaeological and Historical-Artistic Sciences, 1, 2004, pp. 113-145;
A. Mastino, History of Ancient Sardinia, Nuoro, Il Mistrale, 2005.