In 1536, France and Spain went to war again and French corsairs launched a series of attacks on Spanish Caribbean settlements and ships. The next year, a corsair vessel appeared in Havana and demanded a 700-ducat rescate. Spanish men-of-war arrived soon and scared off the intruding vessel, which returned soon thereafter to demand yet another rescate. Santiago was also victim of an attack that year, and both cities endured raids yet again in 1538. The waters off Cuba's northwest became particularly attractive to pirates as commercial vessels returning to Spain had to squeeze through the 90-mile-long strait between Key West and Havana. In 1537–1538, corsairs captured and sacked nine Spanish vessels. While France and Spain were at peace until 1542, beyond-the-line corsair activity continued. When war erupted again, it echoed once more in the Caribbean. A particularly vicious French corsair attack took place in Havana in 1543. It left a gory toll of 200 killed Spanish settlers. In all, between 1535 and 1563, French corsairs carried out around sixty attacks against Spanish settlements and captured over seventeen Spanish vessels in the region (1536–1547).