After the annexation to the Kingdom of Sardinia, the governor of the Romagne, Luigi Carlo Farini, aggregated this village to the province of Modena. The inhabitants protested, and on the fifteenth of December 1860 Sant'Agata returned definitively to that of Bologna. Two years later, with a royal decree of 1862, the comune's denomination was changed from Sant'Agata to Sant'Agata Bolognese: having fought to stay in that province, the village wrote it into its name as well. The coat of arms, on the other hand, has never been formally granted by anyone, and yet it has been in use since the eighteenth century: a golden oak on a blue field. The castle, which is the present old town, was begun in the eleventh century, and its tower — now the bell tower — was completed in 1189 under Frederick Barbarossa; the lower gate still carries the name of Otesia, the Roman municipium that stood hereabouts. In the fourteenth century the houses with their original porticoes were finished, and in those same years the agrarian Partecipanza was born, the institution of collective ownership of the land.
Here things are often made out of other things. The fair was born in the eighteenth century; in 1730 the covering of the canal chiaro was completed, which crossed the centre from gate to gate; and in 1878 the church of the Addolorata was built using the material of the Porta di Sopra, which had been demolished — a gate turned into a church. Palazzo Taruffi, which today is the town hall, has a Bibiena theatre attached, and the public clock goes back to the sixteenth century. Many old remains, instead, were lost in the wars between factions and in the battles between Bologna and Modena, of which Sant'Agata, standing on the border, was always an outpost faithful to the Bolognese. Today the village is known throughout the world for the factory that has its seat here, Lamborghini, with its museum: a firm that had begun by building agricultural machinery.