Whether justifiable or not, these aggressive acts of Drake had much to do with the desire for revenge upon England which led Philip II to prepare for a great invasion of that country. Drake, on his return, in 1580, from the first English circumnavigation of the globe, was knighted by Queen Elizabeth. She now gave him important commands, and from this period at least his career may be regarded in connection with the regular service of his sovereign. In the autumn of 1585 Drake sailed with twenty-five ships against the Spanish Main, harrying the coasts of the West Indies and of northern South America. Cartagena, which he captured in 1586, was the chief port and stronghold of New Granada (now Colombia). By this feat, as also by his "singeing of the beard of the Spanish King" at Cadiz next year, he assailed with telling effect the power with which England was at once to be brought into more serious conflict. The mill of Philip's purpose went grinding on relentlessly. He invited a large fleet of English corn-ships to the relief of his famine-stricken provinces, and then, as they lay unsuspecting in his ports, he seized them every one. Never once was the growing armada out of his mind. This atrocious outrage was but to feed his monster, and swift and sharp was the retribution it earned. It was in the last days of May, and, ere June was out, far and near the seas were swarming with English privateers, and "The Dragon" was unchained. Fortified with letters of marque to release the embargoed vessels, Drake hoisted his flag at Plymouth on the Elizabeth Bonaventura, and there, by the end of July, "in all jollity and with all help and furtherance himself could wish," a formidable fleet gathered round him. Frobisher was his vice-admiral, Francis Knollys his rear-admiral, and Thomas Fenner his flag-captain. Christopher Carleill was there, too, as lieutenant-general, with a full staff and ten companies under him. No such privateering squadron had ever been seen before. It consisted of two battle-ships and eighteen cruisers, with their complement of store-ships and pinnaces; it was manned with a force of soldiers and sailors to the number of two thousand three hundred, and it is not surprising that constant difficulties delayed its departure.