Christopher Columbus, in the service of Spain, first landed in the Americas in 1492. Soon Spanish seamen began to explore the “New World”, beginning with the Caribbean Sea and moving on to the mainland—a region that became known as the Spanish Main. Spain claimed much of Central and South America as its own. The empires of two great American peoples, the Aztecs and the Incas, were conquered and their vast stocks of gold and silver shipped back to Spain. Then in 1545, silver was found at Potosí in modern-day Bolivia. The ships the Spanish used to carry their treasure were called galleons. They formed a fleet known as the Spanish treasure fleet. The sea journey to Europe was threatened by privateers, who were men employed to steal Spain’s treasure by enemy governments, and pirates, thieves who stole for their own gain.

The Spanish Main

The Spanish Main was the name given to the mainland coast around the Caribbean Sea. This region became part of the Spanish Empire from the 16th century. From here, a fabulous amount of goods were shipped to Spain by the treasure fleet. Goods included gold, silver, gemstones, spices, hardwoods and animal hides. The Spanish Main was a magnet for pirates and privateers, so Spain guarded the fleet with war galleons.

The silver came from rich ores inside the Cerro Rico (“Rich Mountain”). The mining town of Potosí soon grew up in the neighbourhood and grew to be one of the largest cities in the Americas. Some 45,000 tonnes of silver was mined between 1546 and the end of the 17th century. The mine labourers, originally local peoples and later imported African slaves, died in their thousands due to the extremely poor working conditions and to poisoning by mercury, a substance used in the process of separating silver from the natural ore.

Treasure and coins

The native peoples of Central and South America made beautifully crafted ornaments, statues and jewellery from precious metals. The Spanish melted down most of the gold and silver they seized from native peoples and turned it into coins or ingots. Their historical value was lost forever.

Gold coins were called “doubloons”. Silver coins were called “pesos”. Pesos de ocho reales were silver coins worth eight reales (real means “royal” in Spanish). They came to be known among pirates as “pieces of eight”.

Ingots

About one fith of the silver and gold was made into coins. The rest was shipped in the form of large ingots. These ingots, or bars, were stamped with both a unique serial number and an additional mark to indicate that the 20% royal tax (quinto) had been paid.

Nueva España Flota

The Nueva España Flota sailed in April to the port of Veracruz in Mexico (called Nueva España, or New Spain). Another fleet, known as the Manila Galleons, crossed the Pacific Ocean from the Philippines bringing goods such as porcelain, silks, ivory and spices (as well as enslaved Filipinos) from China and Japan to Acapulco, on the Pacific coast of Mexico. From here, mule trains shipped the goods overland to Veracruz. The yearly arrival at Acapulco of the Manila Galleons drew pirates to the Pacific coast of Mexico. The galleons, sometimes more than 50 metres (165 feet) long, were the largest ships in the Spanish fleet.

Silver from Potosí travelled on the second of Spain's Indies Flotas. Llama trains carried the silver mined in Potosí across the Andes Mountains and the Atacama Desert to Arica (in present-day Chile) on the Pacific coast of South America. Ships of the South Seas Fleet transported the cargo as far as Panama City. It was then hauled overland across the isthmus (a narrow neck of land) to Porto Bello, an 80-kilometre (50-mile) trek known as the Spanish Silver Train—and a prime target for English, Dutch and French privateers.

Return to Spain

The Nueva España Flota and the Tierra Firme Flota met up in Havana in the spring to embark on the voyage home to Spain. The combined fleet sailed between the coast of Florida and the Bahamas. Laden with cargo, the galleons were vulnerable to storms, running aground on reefs and the threat of pirate attack. Most made it back to Seville in Spain by October or November.