In 1920, Domenico and Attilio Giannini opened an Itala dealership in Rome and began preparing and modifying the cars for competition use, including entry to the Mille Miglia where one of their cars achieved a class win in 1927. When Fiat introduced the Topolino, it was a natural target for the brothers attention and in 1938 they set numerous records with a single seater 500. Following the second world war Giannini continued to develop the small Fiat engines, especially the ohv unit and developed their own engines, first the G1, a sohc 660cc unit and later the G2 which was a dohc 750cc unit.
The Giannini brothers went into partnership with Bernado Taraschi, to build sports cars, using Giannini engines. The name Giaur is derived from a combination of their surname, GIAnnini and the URania name from Taraschi's earlier cars. A single seater was built to comply with the Italian 750cc regulations and when Italy adopted the international 500cc Formula in 1951, a variant of this car with a linered down engine, was produced. The Fiat, four cylinder, engine was placed at the front with a spiral bevel final drive and rigid rear axle. The car was overweight and over complicated compared to the cars Cooper were producing by this time, however Taraschi did enjoy one moment of glory when he won Italy's first 500cc Formula 3 race at Caracalla in 1951.
A revival of 750cc racing in Italy led them to revert back to this Formula in 1954. In August of that year at Senigallia, Bernardo beat all the other 750cc cars but lost to the 500cc Cooper Mk VIII of Stuart Lewis-Evans. During the 1960's and 70s Giannini built modified versions of the new 500 both for road and race and many wins were taken by the Giannini cars. When new rules were introduced requiring production runs of 5,000 for homologation, Giannini returned to modifying road cars and almost all Fiats were tackled in one way or another. The company continues in this tradition today.