From the Annals of the Spanish Sea –  In 1554, three Spanish treasure ships ran aground during near present-day Port Mansfield. The San Esteban, the Espíritu Santo, the Santa María de Yciar, and the San Andrés had set out from Veracruz on April 9.  But a powerful storm in the Gulf of Mexico doomed most of the fleet.  The San Andrés somehow survived.  Incredibly many Spanish sailors were unable to swim and more than half of the crew of the three ships drowned before reaching the beach on Padre Island.  The survivors organized two efforts to return to Mexico.  One small group sailed in a small boat to report back and organize a relief expedition. A larger group of survivors started an overland journey to Mexico in the mistaken belief that it would be a short trip.  Local natives, however, attacked the survivors and only one Spaniard, Fray Marcos de Mena, reached Pánuco.  A salvage expedition arrived at the site of the wrecks within two months, but only recovered about half of the 1,000,000 ducats lost in the Gulf.

The remains of the three ships lay undisturbed until 1967 when a General Land Office employee discovered that a private salvage company was excavating the shipwreck site.  This set off a decades long legal battle over the right to recover artifacts in Texas coastal waters with Texas ultimately securing the exclusive rights over such wrecks.  The find was  considered a major discovery and at the time was believed to be the earliest Spanish material ever recovered from American waters.  Artifacts recovered from the wreck included a small solid-gold crucifix, one gold bar, several silver discs, cannons, crossbows, and three astrolabes.

Photo of recovered artifact from  nautarch.tamu.edu