"... the House of Jérôme was, like had been the Orléans, a family of cadets to the reigning dynasty. This comparison had always loomed high in Napoléon III's mind, and had consistently fed into the distrust he directed at his radical cousin. Prince Napoléon was a radical, and he was not shy about using his status to protect the enemies of his throne, from Victor Hugo to the Proudhon. And the memory of the Orléans "usurping" their Bourbon cousins was still fresh in the minds well into his reign
[1]. After him, Napoléon IV was not quite of his father's mind, however his mother most certainly was. Her son might be sitting strong on the throne, she never let go of her feeling of insecurity, and had made her duty to carry the dynasty, her son's dynasty, to the next step. It thus she was when she received the news of Prince Victor's engagement with Princess Marie Amélie of Orléans.
When in 1873 Rouher and Eschassériaux had worked to formalize the "dynastic alliance" with the Orléans, the question of marriage had not gone further than vague projects. The simple reality was that there were noone to marry back then. Napoléon IV was to be married to Princess Beatrice of the United Kingdom, and the only prospective princes the House of Bonaparte could marry were the children of Prince Napoléon, none of whom had yet reached the adult age. On the Orléans' side, the only prospective brides were among the children of Philip, Count of Paris and head of the house, and François, Duke of Chartes, his brother; but then again, none were of age. Any such project of marriage, unfeasible as it was, was postponed to another day; on the backdrop of the other concessions made by Dowager Empress Eugénie, the question was not deemed critical, yet, to their alliance with the Bonapartes. On 18 July 1880 however, on the day of Prince Napoléon Victor's eighteenth birthday, that was a question that became relevant anew.
Since the return of the Orléans family from exile
[2], they and the Jérômes had found a common ground in being their reigning cousins' cadets, and friendship had followed not far behind. Princess Mathilde, Prince Napoléon's sister, was the key articulation of this rapproachment. Her salon and parties had nothing to envy to the Duchess of Teck's, and she was as much a frequent host of the Duke of Aumale and the Prince of Joinville, as she was a friend - or accomplice - of the Duchess of Uzes. To them, the idea of a union was a natural and logic continuation of the Orléans' return to the high abodes of power in France, and a match between Napoléon Victor and Marie Amélie came to be seen as feasible. To Empress Eugénie however, this match was anything but desirable, and it was behind her back that the small clique plotted its way to the marriage over the next two years.
Later, paraphrasing a saying on trains, Georges Clemenceau would quip in his journal about the whole affair : "
one marriage can hide another". He was here referring to the Prince Impérial, another Napoléon Victor
[3]. Napoléon IV's first son had been born in 1875, and it seemed to most as if a marriage between the Bonaparte heir and Isabelle of Orléans, born in 1876
[4], was possible. The age gap was not too wide, though it was understood any union would have to wait for at least a decade, but it was a project that Eugénie did not particularly mind. Empress Béatrice was yet uncommitted to the idea, but she would accept at the Duchess of Uzes' suggestion, to let the children meet and become play partners during the weekends at Trouville. It then happened invariably that Isabelle would always come to Trouville accompanied, innocently enough, by her eldest sister Amélie. And as innocently, Princess Marie Clothilde, placed in Béatrice's suite by Eugénie to teach her the proper ways of the Roman Catholic faith, would be accompanied at Trouville by her son, Prince Victor.
By Christmas of 1882, following the French expression, the "mass was said" - the die was cast - when Victor confessed his newfound love to his wholeheartedly supportive cousin and Emperor. Eugénie, learning of it the day after, was livid. It had all happened under her nose and she had seen nothing. The feeling of suspicion and betrayal was gripping her altogether. The distrust she had lavished upon Prince Napoléon's house soon began to spread to Beatrice's court where "the crime had been committed", and she began to open the eyes to the danger her daughter-in-law, all ignorant she was of the whole intrigue, posed to her position. But it was too late, or at least it seemed until Henri of Artois, Count of Chambord and head of the Bourbons, died in his exile of Frohsdorf at the peak of the Red Summer of '83."
[1] : Perhaps not entirely unwarranted. King Jérôme and his son were in negotiations with Louis-Philippe, before the revolution of 1848, for him to return from exile and be appointed to the House of Peers, which essentially meant denoucing Louis Napoléon, then in his London exile. The revolution aborted the scheme, but it certainly did not help the Jérômes.
[2] : I may elaborate in a future update on this. ^^
[3] : Named after Beatrice's mother. Prince Napoléon's son would be usually referred as simply Victor, whereas the Prince Impérial would be called Victor Eugène.
[4] : OTL 1878. The OTL schedule of Philippe of Orléans' children after Hélènes is moved a couple years ahead by author's fiat, call it butterfly effect.