The Treaty of Amiens gave Europe a moment's breathing space; the English evacuated Madeira, and the Prince Regent determined on a policy of absolute neutrality. But Napoleon was not to be moved; he had determined on the destruction of Portugal, and it was with the full expectation that he would irritate the Portuguese into declaring war, that he sent General Lannes, one of the most courageous, but one of the roughest and least educated of his generals, as ambassador to Lisbon. Lannes acted in accordance with the expectations of his chief; he insulted the Portuguese Court; he failed to observe the most ordinary customs of diplomatic courtesy; and he finally demanded the instant dismissal of all the ministers who belonged to the English party, and especially of Pina Manique, the Intendant of Police, because he had in former days prosecuted the admirers of the French Revolution. The Prince Regent obeyed, both from fear of France and dislike of the high-handed naval policy of England; and Antonio de Araujo de Azevedo, the head of the French party, became Secretary of State for Foreign Affairs, with the Count of Villa Verde, and the Viscount of Anadia as his colleagues, and Lucas de Scabra da Silva succeeded Pina Manique. Even this humble and prompt submission did not satisfy Napoleon, and in 1804 he replaced General Lannes by General Junot whom he ordered to insist upon Portugal's declaring war against England. For a time, however, he thought it wise to postpone his designs against the country, which he regarded as the most vulnerable province of England, while he was engaged in his great campaigns in Germany, and he even signed a treaty of neutrality with the Portuguese Government. The English were not inclined to submit to this, and in 1806, Admiral the Earl of St. Vincent, General the Earl of Rosslyn, and General Simcoe were sent to Lisbon to remind the Prince Regent of the ancient alliance between the two countries, and to promise ample assistance if Portugal would declare war against France. Dom John declined, and on the advice of his ministers, treated the English ambassadors with something like contempt.
At length, in 1807, having defeated the armies of Austria, Prussia, and Russia, Napoleon again turned his thoughts to his projects for the annihilation of Portugal, which had become more than ever a thorn in his side, since it refused to co-operate in his Continental System for the commercial ruin of England. He resolved at first to act with Spain and Godoy, as Pérignon and Lucien Bonaparte had done, and on the 29th of October, 1807, he signed the Treaty of Fontainebleau, by which it was agreed that Portugal should be conquered by the combined armies of France and Spain, and that the northern provinces of the country should be given to the King of Etruria, in exchange for his Italian kingdom, which Napoleon desired to annex, while the southern districts were to be formed into an independent kingdom for Godoy, Prince of the Peace, and the central provinces were to be held by France. The signature of this treaty was followed by immediate action. Junot moved rapidly across Spain with a French army, and in conjunction with a Spanish force, under General Caraffa, invaded Portugal along the line of the Tagus, while General Taranco and General Solano, with two other Spanish armies occupied the Entre Minho e Douro and the Alemtejo. With amazing rapidity Junot accomplished his march, and the Portuguese people hardly realized that war was imminent, until on the 29th of November, Colonel Le Cor rushed into Lisbon with the news that French soldiers were in possession of Abrantes. This alarming intelligence completely unnerved the Prince Regent, who listened to the strongly-worded advice of Sir Sidney Smith, the commander of an English squadron in the Tagus, to abandon his capital for Brazil, and to leave the English to defend Portugal. Dom John believed this the best course to pursue, and after naming a Council of Regency, he went on board an English ship with his wife, Donna Carlotta Joaquina, his two sons, Dom Pedro and Dom Miguel, his six daughters, and his unhappy mother, Queen Maria Francisca, whose disordered brain seemed to understand what was going on, and whose resistance to the efforts to remove her was painful to observe. The English ships had hardly left their moorings in the Tagus, when Junot at the head of two thousand wearied French soldiers, who had survived the fearful fatigue of his rapid march, entered Lisbon on the 30th of November, 1807.