The Duchy of Parma had been created in 1545 from that part of the Duchy of Milan south of the Po River, which was conquered by the Papal States in 1512.

These territories, centered on the city of Parma, had been given as a fief for Pope Paul III's illegitimate son, Pier Luigi Farnese.

In 1556, the second Duke, Ottavio Farnese, is given the city of Piacenza, becoming thus also Duke of Piacenza, and so the state is hereafter properly known as the Duchy of Parma and Piacenza (Italian: Ducato di Parma e Piacenza).

The Farnese family continues to rule until their extinction in 1731, when the duchy is inherited by the young son of the King of Spain, Don Charles, whose mother Elizabeth Farnese is the Farnese heiress.

He rules until 1735 during the War of the Polish Succession, when Parma is ceded to Emperor Charles VI in exchange for the Two Sicilies.

The Habsburgs only rule until the conclusion of the Treaty of Aix-la-Chapelle in 1748, when it is ceded back to the Bourbons in the person of Don Philip, Don Charles's younger brother, which receives also the little Duchy of Guastalla.

As Duke Philip, he becomse the founder of the House of Bourbon-Parma reigning over the Duchy of Parma, Piacenza and Guastalla (Italian: Ducato di Parma, Piacenza e Guastalla).