Archaeological finds in and around the area of Alghero suggest a degree of social organisation as early as 6000 BC although the history of the modern town really begins in the first half of the twelfth century with the fortification of what had been an obscure fishing port by the Doria family of Genoa.

The town successfully defended itself from assaults by the Pisans and Aragonese until 1353, when, after the conquest of Cagliari and Sassari, a large Spanish fleet, supported by the Venetians, routed the Genoans at the nearby bay of Porto Conte and took possession of Alghero.

Following an uprising in which the Spanish garrison was massacred, the town was subjected to a thorough "ethnic cleansing", in which waves of Catalan settlers displaced the locals, forcing them to settle at Villanova, a mountain village 25km to the south. Laws were passed limiting the number of native Sards who could enter, and compelling them to leave town at the sound of a trumpet signal.

Because of its geographic and strategic importance on Sardinia's north-western coast, Alghero quickly became the foremost port for traffic between Sardinia and Catalonia. From the fourteenth to the sixteenth century, its defences were massively strengthened; most of the ramparts and towers still standing today date from this period, when they sheltered a substantial garrison and fleet, providing a powerful bulwark against seaborne raids on Sassari and the whole western interior.

The town suffered a downturn in its economic fortunes following the expulsion in 1492 of its substantial Jewish community, or Aljama. This forced the Aragonese to reopen Alghero to foreign and Sard traders though the core of the town remained stoutly Catalan in character and culture. Links with Spain were bolstered in 1541, when the emperor Charles V made a historic visit to the town, accompanied by his admiral Andrea Doria the most eminent member of the Genoan dynasty, formerly in the vanguard of the emperor's enemies before becoming his staunch ally.

The two were en route to flush out the corsair Hassan Aga from his lair in Algiers, for which they had assembled one of the biggest fleets ever seen. (The pirate chief was himself a Sard: born of shepherds, he was abducted as a slave, forcibly converted and castrated for harem service, and swiftly rose to become right-hand man to the feared Khair al-Din, or Barbarossa.)

After Sardinia was taken over by the House of Savoy in 1720, Alghero became an increasingly marginalised enclave. The destruction of its landward-facing walls in the nineteenth century was unable to arrest its steady decline, a process that was only halted in the 1960s, with the flow of new money into the town in the wake of its discovery and development as a package tourist resort. The last fifty years have seen the establishment of Sardinia's greatest concentration of hotels and restaurants in Alghero, with a string of new developments along the coast north of the centre.

However, the town's remoteness from the mainland has enabled it to escape total mass-market annihilation, while its well established port has ensured the continuation of the key role of fishing in the local economy. At the same time, the most obvious index of Alghero's distinctive culture, the catalano or Algherese dialect, has largely lost the battle against uniformity.

While old people - many of whom still regard themselves primarily as Catalans - are attached to it, few of the post-1960s generations are at all adept, and the existence of evening classes for locals to learn or perfect their knowledge of catalano is a significant gauge of its present precarious state. Today, the best way to hear the Algherese / catalano dialect is to drop in on one of the church services conducted in the local vernacular at the church of San Francesco.