Beginning in the 16th century, the Spanish treasure fleets transported various metal resources and agricultural goods, including silver, gold, gems, spices, cocoa, silk, and other exotic goods, from the Spanish colonies to the metropole. The Crown of Spain took a fifth of the wares and precious metals of private merchants, a tax known as the quinto.
The treasure fleets were the Caribbean treasure fleet, sailing from there to Spain, and the Manila Galleons which brought Asian wares from the Philippines to Mexico, in exchange for Mexican silver from Acapulco. From Acapulco, the Asian goods were transhipped to Veracruz to join the Caribbean treasure fleet, for shipment to Spain.
Spanish ships had brought treasure from the New World since Christopher Columbus' first expedition of 1492, but a system of convoys started to be developed in the 1520s in response to attacks by French and English privateers. Under this system, two fleets sailed each year from Seville (Cádiz from 1707), consisting of galleons, heavily armed with cannons, and merchant carracks, carrying manufactured goods (and later slaves). One fleet sailed to the Caribbean, the other to the South American ports of Cartagena, Nombre de Dios (and later Porto Bello); after completing their trade the fleets rendezvoused at Havana in Cuba for the return trip.
The fleets which numbered just 17 ships in 1550 had reached just over 50 much larger vessels by the end of the century. In the middle of the next century, that number had dwindled to around half of its peak and continued to shrink. However, the fleet began to expand again as trade gradually recovered from the last decades of the 17th century.