sentences:  Aware of the predations of the Spanish, La Vasseur had Fort de Rocher constructed overlooking the harbor, thus fortifying it from further foreign assault.With its cannons drawing a steady aim at any vessels approaching the harbor the fort gave La Vasseur a high degree of control over the island.In the early 1640s La Vasseur was made governor of Tortuga, but the information conflicts as to when specifically that was (some accounts claim he was governor before arriving on the island, and others say he claimed power after building the fort).