Fort De Soto was fifty years in the waiting and barely two years in the building, and by the time its guns could fire, the war that called it into being was already over. Its story is a lesson in how nations fortify against fear: a coast left undefended for half a century, then armed in a frantic rush when a sudden war scare made the long-ignored danger feel real. Almost everything in this archive's military chapter flows from those few hurried years at the turn of the century.
The idea of fortifying Mullet Key was old long before anyone acted on it. In 1849 a board of Army engineers surveyed the islands at the mouth of Tampa Bay and recommended them as sites for coastal defense; among those engineers was a young officer named Robert E. Lee, more than a decade before the Civil War would make his name. The recommendation was sound and the government did nothing with it for nearly fifty years. Through the Civil War, when Mullet Key played only a minor part in the Union blockade, and through the long quiet decades after, the key Lee had marked sat empty, its strategic value noted and shelved.
What finally built the fort was the Spanish-American War. When the battleship Maine blew up in Havana harbor in February 1898 and the United States went to war with Spain, the nation suddenly remembered how exposed its harbors were. Tampa mattered enormously in that war: it was the main port of embarkation for the invasion of Cuba, the place from which tens of thousands of soldiers, Theodore Roosevelt's Rough Riders among them, shipped out for the fighting. The filibustering and smuggling that had been run out of Tampa to the Cuban rebels had angered Spain, and there was real fear that a Spanish warship might strike at the undefended bay. The recommendations of the Endicott Board, the 1880s commission that had called for modernizing the country's harbor defenses with concrete batteries, minefields, and heavy guns, were pulled off the shelf, and the Army moved fast. Mullet Key and Egmont Key would be fortified together, two posts sealing the channel between them: Fort De Soto on Mullet Key and Fort Dade on Egmont.
Work began on Mullet Key in November 1898. The pace was remarkable. Within the first six months the crews had thrown up a wharf nearly three hundred feet long reaching into the bay, a mess hall, an office, a stable, and quarters for the workers, and had laid a narrow-gauge railroad running from the wharf to a construction plant, with a spur line out to the future battery site to haul the immense quantities of material the mortar emplacements would need. They built, fittingly, with the island itself: the foundations were poured from a concrete made with local seashell, and the walls and ceilings from a mix of shell, stone, and cement, so that the fort is in a real sense made of the bay it guarded. The place was first known simply as the Mullet Key Military Reservation, a sub-post of Fort Dade, until 4 April 1900, when it was given the name it still carries, after the conquistador Hernando de Soto. The first mortar battery was finished in May 1900, and building went on until about 1906, by which time the post counted some twenty-nine structures, a hundred-foot barracks, a hospital, a guardhouse, a bakehouse, blacksmith and carpenter shops, and a storehouse among them.
The cruel irony is that the war was over before the fort was ready. Spain sued for peace in August 1898, only months after construction began and two years before the first guns were emplaced. Fort De Soto never fired a shot at an enemy, because no enemy ever came, and the elaborate defense it represented was already being overtaken by the rapid advance of naval gunnery and warship design. The fort was, in a sense, a monument to a danger that had passed almost as soon as it was felt. Its later history bears the same melancholy stamp: the relentless Gulf began eating away at Battery Bigelow within a generation, and the post would be minimally manned, then abandoned, long before any second war found a use for the island. Fort De Soto stands today not as a place where history was made in battle, but as a near-perfect time capsule of a brief moment of national fear, the most complete surviving Endicott-era fort on the Gulf, built in haste for a war that ended before the concrete was dry.