At the beginning of the seventeenth century a notable change came over the tactics of the Corsairs: they built fewer galleys, and began to construct square-sailed ships. In Algiers, Tunis, and Tripoli the dockyards teemed with workmen busily engaged in learning the new build; and the honour, if such it be, of having taught them rests apparently between England and Flanders. Simon Danser, the Flemish rover, taught the Algerines the fashion of "round ships," in 1606, and an Englishman seems to have rendered the same kind office to the people of Tunis, aided by a Greek renegade, Memi Reïs; where, moreover, another English pirate, "Captain Wer," was found in congenial company at the Goletta by Monsieur de Brèves, the French ambassador.[65] The causes of the change were twofold: first, Christian slaves were not always to be caught, and to hire rowers for the galleys was a ruinous expense; and secondly, the special service for which the smaller galleots and brigantines were particularly destined, the descents upon the Spanish coasts was to some degree obstructed by the final expulsion of the last of the Moors from Andalusia in 1610.[66] That stroke deprived the Corsairs of the ready guides and sympathisers who had so often helped them to successful raids, and larger vessels and more fighting men were needed if such descents were to be continued. Moreover, the Barbary rovers were ambitious to contend with their old enemies for golden treasure on the Spanish main itself; the science of navigation was fast developing; and they felt themselves as equal to venturing upon long cruises as any European nation. Now a long cruise is impossible in a galley, where you have some hundreds of rowers to feed, and where each pound of biscuit adds to the labour of motion; but sails have no mouths, and can carry along a great weight of provisions without getting tired, like human arms. So sails triumphed over oars. The day of the galley was practically over, and the epoch of the ship had dawned. As early as 1616 Sir Francis Cottington reported to the Duke of Buckingham that the sailing force of Algiers was exciting general alarm in Spain: "The strength and boldness of the Barbary pirates is now grown to that height, both in the ocean and the Mediterranean seas, as I have never known anything to have wrought a greater sadness and distraction in this Court than the daily advice thereof. Their whole fleet consists of forty sail of tall ships, of between two and four hundred tons a piece; their admiral [flagship] of five hundred. They are divided into two squadrons; the one of eighteen sail remaining before Malaga, in sight of the city; the other about the Cape of S. Maria, which is between Lisbon and Seville. That squadron within the straits entered the road of Mostil, a town by Malaga, where with their ordnance they beat down part of the castle, and had doubtless taken the town, but that from Granada there came soldiers to succour it; yet they took