Born at the
Ducal Palace of Modena, he was the only son of the third marriage of
Francesco I d'Este, Duke of Modena. His mother was
Lucrezia Barberini, daughter of
Taddeo Barberini and
cardinal on 2 September 1686, he left the ecclesiastical career in 1694 to succeed his nephew
Francesco II as duke. He married
Princess Charlotte Felicitas of Brunswick-Lüneburg (1671–1710), eldest daughter of
Johann Friedrich, Duke of Brunswick-Lüneburg and
Benedicta Henrietta of the Palatinate. He hoped that this marriage to a German princess would provide him needed support from the various German royal houses, including the
Habsburgs, who were connected to his wife by blood.
Rinaldo married Charlotte in
Modena on 11 February 1696. Rinaldo wanted to encourage relations between Modena and Brunswick, whose ruling house was the
House of Hanover. The marriage was celebrated splendidly despite financial problems in Modena; the artist
Marcantonio Franceschini was commissioned to paint a room, the Salone d'onore at the ducal palace in honour of the marriage.
Charlotte died at the
Ducal Palace of Modena after giving birth to a daughter in September 1710. The child also died. She was buried at the Church of San Vincenzo in Modena. Her son succeeded as Duke of Modena in 1737.
His first move as duke was to reduce the price of the grain and to improve the conditions of life of the peasants.
At the outbreak of the
War of Spanish Succession (1702) he declared neutrality, but this did not prevent the French troops from capturing
Modena. The Duke was forced to flee to
Bologna. In 1707, after a long siege in which Rinaldo took part, German troops ousted the French from his capital. In the resulting peace treaty, Rinaldo acquired the
Duchy of Mirandola, but lost
Comacchio. In 1721, he attempted to establish friendlier relationship with France by marrying his son
Charlotte Aglaé d'Orléans, the daughter of
Philippe d'Orléans, Duke of Orléans, the
Régent of France during the childhood of King
Louis XV. Charlotte Aglaé received an enormous dowry of 1.8 million livres, half of which was contributed in the name of the young king, Louis XV, on orders of the Regent. From her adopted country, Charlote Aglaé received a trousseau consisting of diamonds and portraits of her future husband. However the marriage proved troublesome, mainly due to his new daughter-in-law's licentious behaviour.
In order to keep peace at court, Rinaldo had to build for them a separate residence in
RivaltaReggio Emilia. Also a failure was an attempt to obtain the
Duchy of Parma through the marriage of his daughter, Enrichetta, with
Antonio Farnese, Duke of Parma. When the duke died without an heir,
Elisabeth Farnese, the Queen of Spain, acquired the duchy for her son,
Charles III of Spain, a member of the
House of Bourbon .
In 1733 the
War of Polish Succession began. Rinaldo, though nominally neutral, sided secretly for Austria. Again French troops forced him to move to Bologna, but a peace in 1736 was again favourable for the Este, who obtained the
county of Novellara and Bagnolo.
Rinaldo was succeeded by his son