Following the fall of the Western
Roman Empire the historical events of Sardinia split up from those of the
Italian Peninsula. After the short period of the
Vandalic occupation, the island came under
Byzantine rule. During the Byzantine rule the mining industry and the metal working activity scored a certain rebirth and silver became again one of the most important export products of Sardinia, although around 700AD trade traffic in the
Mediterranean Sea became somewhat difficult because of the plunderings of the
Arabs. For Sardinia the steady plunderings of the Arabs along the coast had been, for a long spell of time, an impending danger that provoked the depopulation of wide coastal areas and the migration of the people towards the inner side of the island. More and more isolated from the centre of the Byzantine Empire, Sardinia saw in this period the establishment, for the first time in its history, of a real administrative and political autonomy. The island was reorganised into four sovereign and independent kingdoms: the
Giudicati of
Cagliari,
Arborea,
Torres and
Gallura, after the title of their sovereign (
it. giudice, meaning "judge"). There are only a few documents left of the mining history of the period of the
giudicati, but it is reasonable to maintain that mining industry was not relinquished at all. In 1131 the judge
Gonario II of Torres donated half of the Argentiera of the
Nurra to the primatial church of Santa Maria of Pisa, as evidence of the ever-closer political links between the weak Sardinian States and the Tuscan comune. At the beginning of the 9th century in fact, under the patronage of the Papal Court, that was then ruled by
Benedict XIII, in Sardinian history the two
Maritime republics of
Genoa and
Pisa, that were at first allied against the Muslim emir Musa who had taken possession of some areas of the island, were afterwards competing for the dominion on the weak judge states. The defiance ended up in favour of Pisa. The peace of 1087AD between Genoese and Pisans brought, during the period that immediately precedes the Aragonese conquest, the predominance of Pisa across the whole of Sardinia. From the viewpoint of mining history the Pisan rule seems to be quite well supplied with documentary evidence. The Pisan family of the Counts of
Donoratico, embodied by
Ugolino della Gherardesca, enhanced a new start for the mining industry in his dominions in Sardinia and particularly in what is now Iglesiente. Ugolino operated on a territory of about , called Argentaria del Sigerro for the richness of its underground in silver minerals. He supported moreover the moving into the island of some Tuscan hands, skilled in mining and more generally he tried to repopulate his dominions. The main aim of the demographic policy of the
Gherardeschi was the founding and the development of the town of Villa di Chiesa, now
Iglesias. In the Iglesiente, the Pisans resumed the operations of the Romans by opening new shafts and bringing back to daylight the old veins. The strong mining industry, just like political, economic and social life, was ruled by some laws that were gathered in a codex divided into four books, better known as
Breve di Villa Chiesa. In this codex the regulations of mining industry, particularly the silver prospecting, plays a major role. The crimes against mining were punished with the utmost rigour: the death penalty was provided for those who stole silver or silvery minerals but also for the foundrymen who mined silver from stolen materials. Everyone in the territory of the Argentiera could undertake a mining industry, often for this purpose some companies whose participants (parsonavili) possessed quotations of society (trente) were founded. Some members of these companies, so called "bistanti" confined themselves to tender to advance the necessary amount of money. The operations developed around the digging of ditches and in depth thanks to shafts (
bottini) and tunnels. The ongoing vein or of the mineral lens was followed, so that the operation extension was quite limited. To grab on the rocky mass, picks, wedges and other hand tools were employed; sometimes fire was used to break out harder rocks. The working week started at noon on Monday and ended at noon on Saturday. Miners worked for 12 hours a day and during the week they could not leave their work. During summer season operations were stopped because of the unwholesome climate, being mostly coastal areas stricken by the plight of
malaria. It has been calculated that Sardinian mines had supplied Pisa with almost 15 tons a year of the valuable metal in the period stretching from the end of the 12th century to the beginning of the 14th century. Under the Tuscan comune, in the period of brightest splendour the mines around Villa di Chiesa gave shelter to 6500 workers. In the years around 1326AD Pisa lost its Sardinian dominions to the
crown of Aragon. The loss of the island, but first of all of its silver mines, was the commencing of the fall of the Tuscan city that was pressed on the continent by its rivals
Lucca and
Florence. The Aragonese crown took upon the rights concerning the exploitation of the rich ore bodies of the silver ore in order to avoid disputes between Aragonese nobles for the mineral richness of the zone. The mining industry level in this period was remarkably reduced if compared to the one of Pisan domination. Following the total conquest of the island, the Aragonese tried to enhance the silver mining industry: duties were lightened and also taxes and rights owed to the crown for metals. Such policy though could not return Sardinian mines to their past prosperity. Under Aragonese domination first and Spanish after that, the mining industry knew a continuous decay; Sardinia, that for centuries had been one of the most important productive areas for silver, ended up importing the valuable material that was by then coming in large amounts from the Spanish settlements in the New World. Even in this period Sardinian mines did not totally cease to be active, in fact a small domestic market remained. Under Spanish domination it was decided to subordinate the mining activities to the grant of concessions from the State administration. At least forty concessions for exploration and exploitation of Sardinian ore bodies were assigned. Eight of them were general concessions, extended to the whole territory of the island and eighteen were limited to the circle of Iglesias. The assigners of the territory of the island had to pay to the Treasury 10% of the value of the extracted mineral. The first attempt to enhance the activity of the silver vein of Sarrabus, that had been relinquished for more than one thousand years, dates back to this period. In fact, on 6 June 1622 a certain Gio. Antonio Agus was granted a permit of prospecting around Monte Narba, near the town of San Vito. After no longer than four hundred years the Spanish dominion on Sardinia ended as a consequence of the events connected to the
War of the Spanish Succession and to the attempt of reconquest of Cardinal Alberoni. ==The Savoy Era==