With as much sluggishness as might have been expected from their clumsy architecture, the ships of the Armada consumed nearly three weeks in sailing from Lisbon to the neighbourhood of Cape Finisterre.  Here they were overtaken by a tempest, and were scattered hither and thither, almost at the mercy of the winds and waves; for those unwieldy hulks were ill adapted to a tempest in the Bay of Biscay.  There were those in the Armada, however, to whom the storm was a blessing.  David Gwynn, a Welsh mariner, had sat in the Spanish hulks a wretched galley-slave—­as prisoner of war for more than eleven years, hoping, year after year, for a chance of escape from bondage.  He sat now among the rowers of the great galley, the Trasana, one of the humblest instruments by which the subjugation of his native land to Spain and Rome was to be effected.

Very naturally, among the ships which suffered most in the gale were the four huge unwieldy galleys—­a squadron of four under Don Diego de Medrado—­with their enormous turrets at stem and stern, and their low and open waists.  The chapels, pulpits, and gilded Madonnas proved of little avail in a hurricane.  The Diana, largest of the four, went down with all hands; the Princess was labouring severely in the trough of the sea, and the Trasana was likewise in imminent danger.  So the master of this galley asked the Welsh slave, who had far more experience and seamanship than he possessed himself, if it were possible to save the vessel.  Gwynn saw an opportunity for which he had been waiting eleven years.  He was ready to improve it.  He pointed out to the captain the hopelessness of attempting to overtake the Armada.  They should go down, he said, as the Diana had already done, and as the Princess was like at any moment to do, unless they took in every rag of sail, and did their best with their oars to gain the nearest port.  But in order that the rowers might exert themselves to the utmost, it was necessary that the soldiers, who were a useless incumbrance on deck, should go below.  Thus only could the ship be properly handled.  The captain, anxious to save his ship and his life, consented.  Most of the soldiers were sent beneath the hatches:  a few were ordered to sit on the benches among the slaves.  Now there had been a secret understanding for many days among these unfortunate men, nor were they wholly without weapons.  They had been accustomed to make toothpicks and other trifling articles for sale out of broken sword-blades and other refuse bits of steel.  There was not a man among them who had not thus provided himself with a secret stiletto.

At first Gwynn occupied himself with arrangements for weathering the gale.  So soon however as the ship had been made comparatively easy, he looked around him, suddenly threw down his cap, and raised his hand to the rigging.  It was a preconcerted signal.  The next instant he stabbed the captain to the heart, while each one of the galley-slaves killed the soldier nearest him; then, rushing below, they surprised and overpowered the rest of the troops, and put them all to death.