In the course of the long and intricate negotiations there was one point upon which Louis Philippe laid a special stress—­the candidature of Prince Leopold of Saxe-Coburg.  The prospect of a marriage between a Coburg Prince and the Queen of Spain was, he declared, at least as threatening to the balance of power in Europe as that of a marriage between the Duc de Montpensier and the Infanta; and, indeed, there was much to be said for this contention.  The ruin which had fallen upon the House of Coburg during the Napoleonic wars had apparently only served to multiply its vitality, for that princely family had by now extended itself over Europe in an extraordinary manner.  King Leopold was firmly fixed in Belgium; his niece was Queen of England; one of his nephews was the husband of the Queen of England, and another the husband of the Queen of Portugal; yet another was Duke of Wurtemberg.  Where was this to end?  There seemed to be a Coburg Trust ready to send out one of its members at any moment to fill up any vacant place among the ruling families of Europe.  And even beyond Europe there were signs of this infection spreading.  An American who had arrived in Brussels had assured King Leopold that there was a strong feeling in the United States in favour of monarchy instead of the misrule of mobs, and had suggested, to the delight of His Majesty, that some branch of the Coburg family might be available for the position.  That danger might, perhaps, be remote; but the Spanish danger was close at hand; and if Prince Leopold were to marry Queen Isabella the position of France would be one of humiliation, if not of positive danger.  Such were the asseverations of Louis Philippe.  The English Government had no wish to support Prince Leopold, and though Albert and Victoria had some hankerings for the match, the wisdom of Stockmar had induced them to give up all thoughts of it.  The way thus seemed open for a settlement:  England would be reasonable about Leopold, if France would be reasonable about Montpensier.  At the Chateau d’Eu, the agreement was made, in a series of conversations between the King and Guizot on the one side, and the Queen, the Prince, and Lord Aberdeen on the other.  Aberdeen, as Foreign Minister, declared that England would neither recognise nor support Prince Leopold as a candidate for the hand of the Queen of Spain; while Louis Philippe solemnly promised, both to Aberdeen and to Victoria, that the Duc de Montpensier should not marry the Infanta Fernanda until after the Queen was married and had issue.  All went well, and the crisis seemed to be over, when the whole question was suddenly re-opened by Palmerston, who had succeeded Aberdeen at the Foreign Office.  In a despatch to the English Minister at Madrid, he mentioned, in a list of possible candidates for Queen Isabella’s hand, Prince Leopold of Coburg; and at the same time he took occasion to denounce in violent language the tyranny and incompetence of the Spanish Government.