With the outbreak of the fourth war in 1536, however, trouble for Cuba began. French privateers, little better than pirates in their practices, sometimes, swarmed the Caribbean and the Gulf, preying upon Spanish commerce and raiding Spanish seacoast towns. The first such blow was struck at Cuba in 1537. A fleet of five Spanish ships, richly laden, was about to set forth from Havana for Spain, by way of the Bahama Channel. Just as they spread their sails and weighed their anchors, a venturesome French privateer entered the harbor's mouth. The intruder hesitated at sight of so many vessels, whereupon three of the Spaniards, being well armed as well as laden, as most ships had to be in those troublous days, gave chase. The Frenchman retired, fighting stubbornly, as far as the harbor of Mariel, where he turned at bay and for three days kept up the unequal conflict. Then, just as he seemed preparing to give up the fight and flee, an unfavorable wind struck the Spanish ships, placing them at such disadvantage that their captains ordered them to be abandoned and burned. This was done, but the French boarded one before the flames had made headway, extinguished the fire, and sailed away with the prize. The daring Frenchman then returned to Havana, entered the harbor with the two ships, and proclaimed to the alcaldes and citizens that he would do the place no harm if none was done to him, but that if any attack was made upon his ships, he would sack the town. After a while he went out and sailed away to the west.
At that same time all commerce out of and into Santiago was practically blocked by the presence of French privateers hovering off that port. In April, 1538, an attack was made upon Santiago, and the place was defended in a most extraordinary fashion. A Spanish vessel tried to leave port, met a French vessel returning from a raid on Hispaniola, and tried to scuttle back, but was overtaken and captured at the entrance to the harbor. Next day, having despoiled the prize, the Frenchman sailed into the deep harbor, which never before had been thus invaded, and menaced the town. The town had no defences whatever, and the citizens were unarmed. Guzman, then just at the end of his administration, was furious at his helplessness. He railed against the citizens because they would not rush down to the wharf and repel the invader with clubs and stones. But railing was in vain, and so there was nothing to do but to take to flight inland, which most of the officials and citizens did, carrying all portable treasure with them.