The manner by which the king of Portugal became acquainted with this conspiracy, was for a long time unknown to the court of Spain, nor did the Spanish monarch discover the person who dispatched the archbishop's letters to Lisbon, till another conspiracy was forming against himself. The king of Portugal, as has been already mentioned, kept up a constant correspondence with the enemies of Spain; his ports were open to the French and Dutch fleets; he had a resident both at Barcelona and with the insurgents in Catalonia; and he left no means untried to cause confusion in the very heart of Spain, in order to occupy the mind of Philip the IVth, in a way to give him no time to attend to the affairs of Portugal. The new monarch had already partly succeeded in sowing the seeds of rebellion in the breast of his brother-in-law, the duke de Medina-Sidonia; and their mutual confident the marquis d'Aïamonte, a Castilian nobleman, had completed his seduction. This latter was nearly related to the queen of Portugal and the duke; and the situation of his estate at the mouth of the Guadiana, near the frontiers of Portugal, greatly favoured his secret correspondence with that court. Naturally ambitious, he wished to raise his fortunes, and flattered himself his own elevation would be the consequence of that of the two houses of Braganza and Medina-Sidonia. He was a man of a daring, enterprising character, discontented with the conduct of the prime minister, and possessed of that perfect indifference for life so necessary to all those who engage in great and difficult undertakings. Immediately on the discovery of the archbishop of Braga's conspiracy; the marquis d'Aïamonte wrote secretly to the duke de Medina-Sidonia to congratulate him on the escape of his sister the queen of Portugal, and the rest of the royal family; insinuating at the same time, how nearly it concerned him, that the new monarch should preserve a crown, which must necessarily descend to his own nephews; and that Portugal, from its vicinity to Castile, would ensure him a retreat on any emergency; especially during the ministry of the count-duke whose arrogance and despotic system of politics had no other object than to seek occasions of humbling the grandees. He added, too, it was far from certain that the minister, though his relation, would long permit him to enjoy the government of so large a province in the neighbourhood of Portugal; that this subject was worthy his serious reflections; and that if the duke was willing to be more fully acquainted with his sentiments on the occasion, he would immediately send him a faithful friend, to whom he might safely confide his most secret thoughts.