As all the countries of Sardinia, also Osini is characterized by traces of antiquity that go up again to the II and III Millennio a.C. even if the first news goes up again to the 1316 graces to a register of the imposed Pisanes registered with the name of the old country Uzini; after the conquest of the island from the Aragonese ones, Osini together with the rest of the countries Ogliastrini, kept on paying the taxes to the Spanish vassals with which it treated, in particular meetings, of the general problems of the small feuds of the zone; each represented by his/her own mayor. The foundations of Osini have origin in 1670-1680 in which the formulation of the parish registers and the censuses is had even if the first believable results of calculation were had in 1780-1790 in which of 499 inhabitants figuravano16 been born a year. Actually to 1961-1968 the population grew after that a decrease of the number of inhabitants was had because of a due emigration to the distribution of the vineyards; it is really in this period that the country coastlines draw advantage being more also populated for the existence of fertile earths, it was so that Osini succeeded in establishing good relationships with the tourists that visited the mountain of the Taccu that hides today still the caves and the nuraghis. In 1951 with the flood the country became inagibile forcing the inhabitants to live and to reconstruct him buildings near the railway station; for first thing the Town hall, the Church and the schools were built for then arriving to the popular houses; more before the concession of new contributions and free earths it was had. The fundamental cause of the abandonment they were the sources that abundant of water they penetrated among the walls of the houses, in fact Osini Vecchio was built on three sources that he/she anchors today they feed the present fountains in the abandoned roads; the bridge of the provincial road was overwhelmed and brought away accompanied from some houses in outskirts. All the sources are reputed of big goodness, inside the inhabited area they are three present of it said: "Riu deis Prunas", "Funtanedda" and "Murrai"; Murrai and Prunas always flow full of water, they form rivulet with the influence of other sources and they pour him in the river Sarcerei and in other drainages coming from the Taccu. We remember that the river Sarcerei is fed by the snow that in winter it loosens him in the zone of Lose-liana that raising the levels of the water is not facilitated the ford.