[citation needed] At the outbreak of World War I he enlisted as an officer with the British Armed Forces and saw action in Flanders where he contracted a virulent form of rheumatism that caused his death at the age of 42.

[1] Luís was born at Petrópolis on 26 January 1878, to Prince Gaston d'Orléans, Count of Eu, and Isabel, Princess Imperial of Brazil.

[2] His name in full was Luís Maria Filipe Pedro de Alcântara Gastão Miguel Rafael Gonzaga.

[5] While on a trip to Europe with his family, an earthquake occurred on 23 February 1887, and while his older brother Pedro appeared very nervous and cried, Luís simply stood calm and showed no emotions.

[5] Gaston affirmed in another letter, written in March 1890, that "Baby Pedro [was] always notable for laziness and ineptness," while "Luís does the identical course work all by himself with admirable distinction and capacity.

"[5] The prince very early showed the interest in literature that would result in his authorship of several books about his travels around the world, such as Dans les Alps, Tour d´Afrique, Where four empires meet and Under the Southern Cross.

As they had not been able to take anything with them, except for a few personal objects that they could carry with their hands, the imperial family saw itself in a poor financial situation that was only made worse by Pedro II's refusal to accept the five thousand contos of Réis offered initially by the new republican government.

[4] In 1890, fifteen-year-old Pedro, thirteen-year-old Luís, and their younger brother Antônio (nicknamed "Totó"), moved along with their parents to the outskirts of Versailles.

[14] After he returned to France in 1907 he planned an ambitious project to defy the decree banishing the imperial family from Brazil by travelling to Rio de Janeiro.

[16][17][18][19][20][21][22] I Prince Pedro de Alcântara Luís Filipe Maria Gastão Miguel Gabriel Rafael Gonzaga of Orléans and Braganza, having maturely reflected, have resolved to renounce the right that, by the Constitution of the Empire of Brazil, promulgated on March 25, 1824, accords to me the Crown of that nation.

I declare, therefore, that by my free and spontaneous will I hereby renounce, in my own name, as well as for any and all of my descendants, to all and any rights that the aforesaid Constitution confers upon us to the Brazilian Crown and Throne, which shall pass to the lines which follow mine, conforming to the order of succession as established by article 117.

Before God I promise, for myself and my descendants, to hold to the present declaration.Cannes October 30, 1908 signed: Pedro de Alcântara of Orléans-Braganza[23] This renunciation was followed by a letter from Isabel to royalists in Brazil:November 9, 1908, [Castle of] EuMost Excellent Gentlemen Members of the Monarchist Directory,With all my heart I thank you for the congratulations upon the marriages of my dear children Pedro and Luís.

I believe that this news must be published as soon as possible (you gentlemen shall do it in the way that you judge to be more satisfactory) in order to prevent the formation of parties that would be a great evil for our country.

I give you all my friendship and confidence,The marriage of Luís and Maria Pia was celebrated on 4 November at Cannes, and that of Pedro and Elizabeth ten days later at Versailles.

[25] His efforts to reverse the damage caused by the imperial family's inertia was valued by their supporters, and in 1909 he presented a political manifest to the Brazilian monarchists with the intent to restart the stalled campaign.

[8] Some of the letters from the prince reveal his plans to restore the monarchy, such as the one written for Martim Francisco de Andrada III:[26] "it costs me so much to be here with crossed arms, when I think that a handful of determined men would be enough to pull out our Fatherland from the claws of the adventurers who explore it".

As for me, I judge both the candidates 'undesirable'; but as we have to choose, I would pick Rui "[Barbosa]", whose partisans represent the element more reasonable and with bigger prestige in the country.

"The prince was active from 1907 through to his death in 1920, and argued in favor of federalism, obligatory military service and an improvement in the quality of life for laborers.

[8] Luís defended ideas that were well ahead of his time and the necessity to guarantee worthy conditions of subsistence for the Brazilian workers would only be observed thirty years later during the dictatorship of Getúlio Vargas.

[26] The progressive vision of Luís made him a target for accusations of being a "socialist" and a "radical" when, in reality, his intent was to hinder the work force from adhering to socialism, communism, or even anarchism.

[8] The start of World War I in August 1914 and the invasion of France by Germany made it possible for Luís to once more prove his idealism and activism as, in his own words, he was a "soldier heart and soul".

[4] While fighting in the trenches of Flanders in 1915 Luís contracted an aggressive type of bone rheumatism that left him very weak and incapable of walking.