Emilia takes its name from the Via Aemilia, a Roman road constructed by the consul Marcus Aemilius Lepidus in 187 BCE to connect Rimini with Piacenza.

The Duchy of Ferrara and Comacchio remained under the House of Este until the death of Alfonso II in 1597, when they were claimed by Pope Clement VIII as vacant fiefs.

[1] Modena and Reggio, which were legally Imperial fiefs, but had in fact formed part of the Ferrara duchy, became thenceforth separate dukedoms in personal union under a branch of the house of Este.

The County of Carpy [it] passed to the house of Este in 1530 after the dispossession of the Pio di Savoia family for 'felony' decreed five years earlier by Emperor Charles V, and was elevated to a principality in 1535.

In 1728 another branch of the same House, which had ruled the County of Novellara and Bagnolo for almost 350 years, had also died out, but in this case the fiefdom was granted in 1737 by Emperor Charles VI to Duke Rinaldo I of Modena and Reggio in recognition for his services during the War of the Polish Succession.

Administratively it comprises the provinces of Piacenza, Parma, Reggio Emilia, Modena, Bologna (except for the commune of Imola and Dozza, and the valley of the Santerno) and Ferrara.

The region corresponds approximately to the ancient Cispadane Gaul which, under the Augustan territorial organisation of Italia c. 7 CE, became Regio VIII Aemilia.