The founder is MANFREDO I, one of the sons of the marquis Bonifacio del Vasto (d. 1130), who settled with his brother Guglielmo in the territories of the ancient county of Auriate. Manfredo long held shared possessions with his brother Guglielmo, founder of the marquises of Busca. Around 1175 MANFREDO II was already styled marquis of S., where he had his residence, but even between 1202 and 1212 he was occupied in purchasing from the marquises of Busca rights and properties they held in S. They were faithful vassals of the Swabian emperors, yet Manfredo II did not hesitate to render homage to Otto IV. During the 13th century, MANFREDO III and TOMMASO I were assiduous and industrious in gathering domains to expand their little state, which was confined to the valleys of the Varaita, Moira, and Grasca; they managed to retain only a few other lands in the valleys of the Tanaro and Po. A serious blow to the organization of the marquisate was the formation of the new Commune of Cuneo; the Commune of Asti was also hostile. The marquises, in response, allied themselves with the Commune of Alba. In 1213 the first ties were formed with the counts of Savoy: Manfredo II and Tommaso I of Savoy promised mutual aid and arranged marital ties.
In 1215 Adelasia of Montferrat, regent for her nephew Manfredo III, agreed to render homage to the count of Savoy for the land of Borge. Of great importance is the figure of TOMMASO I (1244–1266), who, while escaping the pressure of the Angevins on one side and the Commune of Asti on the other, managed to organize and expand the marquisate. MANFREDO IV, at the beginning of the 14th century, upon the extinction of the Aleramici of Montferrat, attempted to claim their inheritance, but he was opposed by other relatives, the Paleologi of Byzantium. The 14th century saw grave internal struggles within the family of the marquises of S.: these were provoked by the dispute between Federico I, son of Manfredo IV, and the claimant to the succession, Manfredo of Condé. The conflicts between the two families intertwined with those of the marquisate with the Savoia-Acaia of Pinerolo and the Paleologi of Montferrat.
In 1343 TOMMASO II, to secure aid against the Condé, who persisted in their opposition, rendered homage to the dauphin of Grenoble. Umberto II reconfirmed him in 1354 in favor of the new dauphin Charles of France. In this way, the marquis sought to escape the influence exercised over his domain by the Visconti of Milan and the counts of Savoy. In 1356 Tommaso II took advantage of the anti-Visconti league to occupy Cuneo and attempt a resumption of expansion, but this was no longer possible. Against the new marquis FEDERICO II rose the powerful count of Savoy, Amedeo VI, mindful of ancient ties and indignant that Federico had rendered homage of the marquisate also to Bernabò Visconti (1360). In 1363 the count of Savoy invaded the marquisate, besieged S., and forced Federico to render homage. But the marquis, once free, hastened beyond the mountains to render homage to the dauphin, only to renew it to Amedeo VI in 1364. This double policy provoked protests from the count of Savoy in Grenoble, and in Paris the matter was taken up by the Parliament of Paris.
In 1375 the marquis entrusted his advanced stronghold of Carmagnola to the troops of the Innesche. The struggle between the counts of Savoy and the marquises continued throughout the 15th century. Count Rosso again attacked the marquis in 1386, who found support, as usual, from the Visconti on one side and the Council of the Innesche on the other. Amedeo VIII again took up the struggle against Tommaso III (1396–1416, a patron and man of letters): besieged in S. in 1413, the marquis had to yield and render homage to the victor. Now the marquises seemed resigned to submitting to Sabaudian sovereignty: Ludovico I (1416–75) and Ludovico II (1475–1505, a man of letters) repeatedly rendered homage. Yet secretly they secured support from Italian powers hostile to the Savoys. After the death of Louis XI, the question suddenly arose again in the Parliament of Paris: Ludovico, summoned to render homage to the King, sought to impose conditions, until in 1485 an order for the sequestration of the marquisate was issued from Grenoble. The Duke of Savoy protested and ordered the marquis to render him homage; and since negotiations came to nothing, in 1487 he attacked the marquisate and occupied II. The marquis, having taken refuge in France, the following year managed to reconquer his state. The question then remained open and unresolved due to the death of the Duke of Savoy Charles I.
Marquis Ludovico II was now entirely devoted to France. He supported Charles VIII in his descent into Italy and the expedition to Naples, as he later did for Louis XII, whom he accompanied to Naples. After Ludovico II’s death in 1504, the marquisate was governed for his underage sons by his widow Margherita of Foix. The new marquis MICHELE ANTONIO, utterly devoted to France, followed Louis XII and Francis I in their wars until he died at Aversa in 1524. His brother and heir Giovanni Ludovico, a partisan of Charles V, was disinherited by the marquis in favor of his third son FRANCESCO. Now the fortunes of the marquisate became closely tied to the internal struggles of the marquessal family. Giovanni Ludovico managed to conquer S., but was driven out by Francesco, aided by the French: Francis I confiscated the marquisate and granted it to Francesco as a fief. Then Francesco switched to the imperial side; the King of France granted the marquisate again to Giovanni Ludovico, who also went over to the imperial side. The King of France then granted the fief of S. to the last of the brothers, GABRIELE, who died, it was said, by poison, in 1548. The communes of the marquisate, assembled in Parliament, invited the King of France to annex the marquisate to France (1 August 1548); this annexation lasted until the Treaty of Lyon (17 January 1601), which assigned it to the House of Savoy.