During the ninth century AD, after a period of human absence, a small town arose with a Byzantine church (the Church of San Salvatore).
When the Byzantine influence left Sardinia, the southern part of the island was controlled by the Judicate of Cagliari.

After the fall of the Judicate in 1258, south-western Sardinia (the curatorias of Cixerri and Sulcis) was assigned to the Della Gherardesca family; the Cixerri region was controlled by Ugolino della Gherardesca.
The count took advantage of the region's silver resources and established a city: Latin: Villa Ecclesiae (Churchville), renovating old buildings and constructing new ones.
The Della Gherardesca family built the medieval Castle of Salvaterra, defence walls, a hospital and an aqueduct.

After Ugolino's March 1289 death in Pisa's Tower of Muda (where he was imprisoned in the summer of 1288 for sedition and treason, his Sardinian holdings in the Cixerri reason were inherited by his son, Guelfo della Gherardesca; escaped from Pisa in 1288, he had settled in the Villa di Chiesa.
Guelfo, hostile to the Pisan government, tried to seize one-sixth of the former Judicate of Cagliari (Sulcis) owned by Gherardo della Gherardesca's heirs and occupied Villamassargia's Castle of Gioiosa Guardia.
Pisa's response was swift; in 1295 republican troops, supported by the forces of Marianus II of Arborea, attacked Villa di Chiesa.
Guelfo was wounded near Domusnovas; after trying to escape to Sassari, he died from an infection in the hospital of Siete Fuentes.
Villa di Chiesa was briefly administered by Arborea before falling under Pisan control between 1301 and 1302.

Under Pisan domination, Villa di Chiesa was one of the most important and populous cities on Sardinia thanks to its lead and silver resources.
At the beginning of the 14th century, its mines produced an estimated 10 percent of Europe's circulating silver.
The city, primarily inhabited by Sardinians and Pisans, also housed other communities from Tuscany and the Italian Peninsula, Corsica and Germany.
The city was governed by the Breve di Villa di Chiesa, its original legal code, a 1327 version of which is preserved in the municipal archives.
A mint was established in the city.

Conquered by the Aragonese on February 7, 1324 after an over seven-month siege, Villa di Chiesa was the first Sardinian city to fall to the Iberians and the first city of the new Kingdom of Sardinia to be recognised as a royal city in June 1327.
During the Aragonese period, the city's name changed from Villa di Chiesa to Iglesias.

During the transition from Pisan to Aragonese rule, 6,000–7,000 people lived in Villa di Chiesa; however, the Black Plague of 1348 killed much of the population.
In late 1353 a revolt began against the Aragon government, siding with Marianus IV of Arborea (who had begun hostilities against the Crown of Aragon).
After the 1355 peace of Sanluri, the city returned to Aragon; in 1365, with the resumption of a conflict between the Judicate of Arborea and the Kingdom of Sardinia, Villa di Chiesa was recaptured by Marianus IV of Arborea.
The city remained in Arborean hands until 1388 when, after the treaty between Eleanor of Arborea and John I of Aragon, it was returned to the Aragonese.
In 1391 the city again revolted against the Aragonese, welcoming the judge's army led by Brancaleone Doria.
It was seized by the Iberians in the summer of 1409.

In 1436, Alfonso V of Aragon gave the city in fief to Eleonora Carroz for 5,000 gold florins; however, after paying a ransom Villa di Chiesa regained the status of a royal city in 1450.
During the ninth century AD, after a period of human absence, a small town arose with a Byzantine church (the Church of San Salvatore). When the Byzantine influence left Sardinia, the southern part of the island was controlled by the Judicate of Cagliari.
After the fall of the Judicate in 1258, south-western Sardinia (the curatorias of Cixerri and Sulcis) was assigned to the Della Gherardesca family; the Cixerri region was controlled by Ugolino della Gherardesca. The count took advantage of the region's silver resources and established a city: Latin: Villa Ecclesiae (Churchville), renovating old buildings and constructing new ones. The Della Gherardesca family built the medieval Castle of Salvaterra, defence walls, a hospital and an aqueduct.
After Ugolino's March 1289 death in Pisa's Tower of Muda (where he was imprisoned in the summer of 1288 for sedition and treason, his Sardinian holdings in the Cixerri reason were inherited by his son, Guelfo della Gherardesca; escaped from Pisa in 1288, he had settled in the Villa di Chiesa. Guelfo, hostile to the Pisan government, tried to seize one-sixth of the former Judicate of Cagliari (Sulcis) owned by Gherardo della Gherardesca's heirs and occupied Villamassargia's Castle of Gioiosa Guardia. Pisa's response was swift; in 1295 republican troops, supported by the forces of Marianus II of Arborea, attacked Villa di Chiesa. Guelfo was wounded near Domusnovas; after trying to escape to Sassari, he died from an infection in the hospital of Siete Fuentes. Villa di Chiesa was briefly administered by Arborea before falling under Pisan control between 1301 and 1302.
Under Pisan domination, Villa di Chiesa was one of the most important and populous cities on Sardinia thanks to its lead and silver resources. At the beginning of the 14th century, its mines produced an estimated 10 percent of Europe's circulating silver. The city, primarily inhabited by Sardinians and Pisans, also housed other communities from Tuscany and the Italian Peninsula, Corsica and Germany. The city was governed by the Breve di Villa di Chiesa, its original legal code, a 1327 version of which is preserved in the municipal archives. A mint was established in the city.
Conquered by the Aragonese on February 7, 1324 after an over seven-month siege, Villa di Chiesa was the first Sardinian city to fall to the Iberians and the first city of the new Kingdom of Sardinia to be recognised as a royal city in June 1327. During the Aragonese period, the city's name changed from Villa di Chiesa to Iglesias.
During the transition from Pisan to Aragonese rule, 6,000–7,000 people lived in Villa di Chiesa; however, the Black Plague of 1348 killed much of the population. In late 1353 a revolt began against the Aragon government, siding with Marianus IV of Arborea (who had begun hostilities against the Crown of Aragon). After the 1355 peace of Sanluri, the city returned to Aragon; in 1365, with the resumption of a conflict between the Judicate of Arborea and the Kingdom of Sardinia, Villa di Chiesa was recaptured by Marianus IV of Arborea. The city remained in Arborean hands until 1388 when, after the treaty between Eleanor of Arborea and John I of Aragon, it was returned to the Aragonese. In 1391 the city again revolted against the Aragonese, welcoming the judge's army led by Brancaleone Doria. It was seized by the Iberians in the summer of 1409.
In 1436, Alfonso V of Aragon gave the city in fief to Eleonora Carroz for 5,000 gold florins; however, after paying a ransom Villa di Chiesa regained the status of a royal city in 1450.
Iglesias, Sardinia