Comedie Francaise
In the comedy that was the Third Republic, Henry, comte de Chambord, may lay claim to being the protagonist. For it was Henry, the last, best hope of the Monarchists, who had caused the birth of the Republic due to his intransigence. And it was Henry, woe of the monarchists, who caused the fall of the Republic.
Henry had united the Orleanist and Legitimist claims to the throne in a time when the Monarchist Right held the National Assembly. But he refused to honor that symbol of Republicanism, the French tricolore, and so the National Assembly was unable to crown him as they desired. Waiting for him to die, these monarchist deputies formed the Third Republic- the government that would in the words of Adolphe Thiers, "divide us least." Henry's inability to die before sentiment swung back to the Republicans seemed to cement the Third Republic into place. But French history is never as simple as it seems.
From the time of Presidente Mac-Mahon's Moral Order, Pope Leo XIII had been plotting to bring French Catholics into the Republic. The death of the comte de Chambord in 1883 seemed a catalyst to separate Catholics from the monarchist movements, and Leo XIII would act on this, albeit ponderously as all Papal governments do.
In 1887, Father Charles Lavigerie, who had revived the See of Carthage and drawn praise for his missionary efforts in North Africa even from Republicans, acted upon the Pope's initiative, inviting the officers of the Mediterranean Squadron and of the French Foreign Legion to a luncheon, where the Peres-Blancs (White Fathers) sang the Marseillaise and the Father gave a speech on reconciliation with the Republic, rescinding his earlier monarchist sentiment- sentiment that had come from personal loyalty to Henry.
The Rallying of the Catholics to the Republic (Ralliement des Catholiques à la République) was not a singular event. The release later in the year of the Papal Encyclical, Rerum Novarum, provided a blueprint for French Catholics to participate in the French Republic. [1] Father Lavigerie continued to advocate for Catholic participation in the Republic as did other, lesser priests and Catholics across the whole of France began organizing in earnest, inspired by the Rerum Novarum. These developments would go on to be key in the Boulangist Crisis of 1899....
[1] This, essentially, is the POD. An earlier Rerum Novarum and Rallying of the Catholics to the Republic. TTL's Rerum Novarum is much less detailed and quite obviously targeted towards France.