Born in Turin, Maurice was the fourth of the five legitimate sons of Charles Emmanuel I, Duke of Savoy and his wife Catalina, Infanta of Spain, daughter of King Philip II.

Following what was the custom for the younger members of Italian princely families, Maurice was educated for a life in the Church, and then sent to the papal capital to promote the interests of the House of Savoy.

The House of Savoy was known for its close relationship with the Theatines, and the Cardinal propagated this interest in religious orders by supporting the Oratorians, who were particularly dear to his heart because of the special devotion he felt towards their founder, Philip Neri.

During his sojourn in Rome, he transformed his palace in Monte Giordano [it] (the former Palazzo Orsini) into a magnificent court, characterized by intellectual and artistic endeavors.

Various artists resided at the court, among them his private painter Giovanni Giacomo Semenza, the poet Ludovico d'Agliè, and the composer Michelangelo Rossi.

The Cardinal patronized a broad range of Rome's cultural elite, including the historian-orator Agostino Mascardi, the artists Domenichino and Antonio Tempesta, and the musicians and composers Sigismondo d'India and Stefano Landi.

The "Principisti", had considerable support among ordinary Piedmontese, who resented the French presence;[5] the "Madamisti" included a number of powerful families, notably the d'Aglié clan.

They held the fortress inside the city walls for 155 days while it was besieged by soldiers of Marie Christine and of the French general Henri, Count of Harcourt.