The exchange of the young Infanta and Mademoiselle de Montpensier was on the Île des Faisans ("Isle of Pheasants") and was the site where their common ancestors, Louis XIV and Maria Theresa of Spain, had met in 1660.

The young Infanta was nicknamed the l'infante Reine ("Queen-Infanta")[2] as the couple were not to be married until Mariana Victoria reached a more mature age.

[3] According to the mother of the Regent, Elizabeth Charlotte of the Palatinate, Mariana Victoria was the "sweetest and prettiest little thing" and had considerable wit for her age.

Under the influence of the Prime Minister Louis Henri, Duke of Bourbon, and his mistress Madame de Prie, the decision was made to send the seven-year-old Mariana Victoria back to Spain on 11 March 1725.

The situation was not helped by the Spanish rejection of Louise Élisabeth d'Orléans, whose husband died having ruled as Louis I of Spain for only seven months.

Mariana Victoria would marry the Infante José, "Prince of Brazil", son and heir of João V of Portugal.

[7] Mariana Victoria married the Prince of Brazil (traditional title for the Portuguese heir to the throne) on 19 January 1729 at Elvas in Portugal.

The Prince of Asturias (traditional title for the Spanish heir to the throne) married the Infanta Bárbara the next day at Badajoz.

When her other daughter Infanta Doroteia was proposed as a wife for the future Philippe Égalité Mariana Victoria again refused to the match.

Her youngest daughter Infanta Benedita married José, Prince of Brazil, Mariana Victoria's grandson.

[9] At the death of her father-in-law, King John V in 1750, her husband became the ruler of the Portuguese Empire which had significant territories in South America.

Pombal later ordered the execution of all members of the noble family and it was only at the intervention of Mariana Victoria and her daughter, the Princess of Brazil, that some women and children were spared.

Throughout Maria I's reign Mariana Victoria exerted significant influence on her daughter, who would often ask her mother's advice on matters of state.

[10] When her daughter had assumed government, Mariana Victoria took it upon herself to improve relations with her native Spain, which was ruled by her older brother Carlos III.

Leaving Portugal on 28 October 1777, Mariana Victoria travelled to Spain where she stayed for just over a year, residing both in Madrid and at Aranjuez.