If Richelieu thus imprudently indulged his passion or his pique, he redeemed the error by activity and exertion unusual to the age. He at once formed the project of attacking the Huguenots in their chief stronghold of La Rochelle. Buckingham, the English minister, could not fail to attempt the relief of this sea-port, and the cardinal anticipated the triumph of personally defeating a rival. He accordingly himself proceeded to preside over the operations of the siege. To render the blockade effectual, it was requisite to stop up the port. The military officers whom he employed could suggest no means of doing this. Richelieu took counsel of his classic reading, and having learned from Quintus Curtius how Alexander the Great reduced Tyre, by carrying out a mole against it through the sea, he was encouraged to undertake a similar work. The great mound was accordingly commenced, and well-nigh finished, when a storm arose and destroyed it in a single night. But Richelieu was only rendered more obstinate: he recommenced the mole, and was seen with the volume of Alexander's History in his hand, encouraging the workmen and overruling the objections of the tacticians of the army. The second attempt succeeded, the harbor was blocked up, and the promised aid of England rendered fruitless. The cardinal triumphed, for La Rochelle surrendered. In his treatment of the vanquished, Richelieu showed a moderation seldom observable in his conduct. He was lenient, and even tolerant, toward the Huguenots, content with having humbled the pride of his rival, Buckingham. La Rochelle was no sooner taken, and Richelieu rewarded by the title of prime minister than he resumed those projects of humbling the House of Austria, in which he had previously been interrupted. A quarrel about the succession to Mantua afforded him a pretext to interfere; and he did so, after his fashion, not by mere negotiations, but by an army. This expedition proved a source of quarrel between him and the queen-mother, Mary de Medici, who hitherto had been his firm and efficient friend. The voice of the conqueror of La Rochelle triumphed in council, and his project in the field. The French were victorious in Italy, and the minister equally so over the mind of the monarch.