San Esteban was a Spanish cargo ship that was wrecked in a storm in the Gulf of Mexico on what is now the Padre Island National Seashore in southern Texas on 29 April 1554.

Almost all the others died of thirst or starvation, or were killed by hostile local Karankawa Indians during their attempt to walk back to safety.

Many artifacts have been recovered and are held in the Corpus Christi Museum of Science and History, including the world's oldest mariner's astrolabe with a confirmed date.

[1] The fleet had a difficult outbound voyage, suffering from bad weather, accidents and skirmishes with pirates.

The ships were unloaded and refitted slowly, and only one was prepared to sail for Havana to join the fleet for the return journey to Spain that year.

[1] Oral tradition holds that a priest in Mexico predicted that there would be a disaster before the ships set sail, but that his warning was ignored.

[2] The four ships left Vera Cruz on 9 April 1554, carrying over 400 people and valuable treasure and cargo.

[3] The passengers included wealthy citizens, merchants and former soldiers,[4] but there were also a few prisoners and five Dominican missionaries who had decided to return to Spain.

[5] The ships carried barrels holding over 85,000 pounds (39,000 kg) of silver coins and disks that had been minted in Mexico City.

[1] Due to prevailing winds and currents, the best route from Veracruz to Havana ran along the shore of what became Texas and Louisiana.

[4][a] Santa Maria de Yciar sank about 42 miles (68 km) north of the Rio Grande's mouth, where the Mansfield Channel is today.

[10] The other survivors tried to walk south along the shore, not realizing that the nearest Spanish outpost was Tampico, 300 miles (480 km) away.

[11] One, Brother Marcos de Mena, was left for dead after receiving multiple arrow wounds.

[5] Treasure hunters who knew of them and beachcombers searching at random found traces of Spanish coins and fragments of ships on the Padre Island beaches throughout the 20th century.

[9] The search intensified after dredgers accidentally destroyed Santa Maria de Yciar late in the 1950s.

[9] Platoro's exploration and retrieval of objects from the site started a long-running argument with the state of Texas about ownership of the artifacts.

It also triggered the Texas legislature to pass the Antiquities Code in 1969 to prevent unauthorized excavation of future finds.

On this basis, due to a concern that the excavation should be conducted using scientific archaeological methods, and since this was the oldest shipwreck site to be examined in the Western Hemisphere, the state launched a suit against Platoro.

[14] The Antiquities Conservation Facility (ACF) was set up at TARL to study the material found by Platoro.

After the ACF was closed these principles were carried forward in the Conservation Research Laboratory at Texas A&M University.

[3][d] In 1970, the Texas Antiquities Committee commissioned the Institute of Underwater Research to survey about 20 miles (32 km) of the coast over a one-month period.

[9] Where the magnetometer indicated that iron was present, they used a "blower" to make a vertical jet of water that blew a 5 feet (1.5 m) layer of sand and shell away from the Pleistocene clay bottom and exposed the artifacts of the wreck.

[19] The divers made careful maps of the material they recovered, but had no way of determining on the spot what was inside the metal conglomerates encrusted by marine growth.

[9] Each encrusted conglomerate of concreted material was carefully documented with photographs, radiographs where practical, and detailed conservation records.

[20] They then subjected the metal and wood objects to complex and time-consuming processes to remove the products of corrosion and preserve them from future degradation.

[8] Other finds included ship's fittings, tools and a cannon made by welding together iron bars.

[8] The stern/keel section of the San Esteban is similar to other wrecks of the period, and contributes to a view of ship construction at the time.

Several conglomerates held the exoskeletons of cockroaches, providing the first evidence of shipment of these insects between Europe and the Americas.

Some locally-made items included prismatic obsidian blades and a polished nodule of iron pyrite for use as a mirror.