I found all of this great information on Wikipedia about the Perdido Key area.
History, geography, ecology, references and all sorts of links that just get my geeky, information loving, heart pumping.
"In 1693 noted cartographer and scientist Don Carlos Siquenza was sent by the Spanish government to locate the entrance (to Perdido Bay). Even after he located the mouth of the bay, he was still unable to find a waterway deep enough to sail through. According to legend, Siquenza's ship had been blown off course as he was again searching for the pass into the deep inland waters. The ship was spotted by an Indian chief camped with his tribe at Bear Point. As the chief was walking along the water he spotted Don Carlos Siquenza attempting to reef his sails and offered to guide Siquenza and his men to a connecting deep water channel from the Gulf of Mexico into the more tranquil bay. When the search party finally located the elusive bay, they called it "Perdido", which in Spanish means "lost" or "hidden"." - from Wikipedia
Thought I'd share some other good sites for area information too.
Gulf Islands National Seashore
Historic Pensacola Village
Did you know that
Geronimo lived for a time at Fort Pickens as a U.S. prisoner?
Have fun exploring.