Spain jealously guarded her possessions because of the wealth found there. She considered any interlopers-particularly those from northern Eurpose-pirata and treated them accordingly. The Spaniards seized ships and tortured, enslaved, or slew violators. This persecution united the pirates against Spain, and the rich treasure ships stirred their lust to acquire the gold, silver, and gems for themselves.
From Seville, the House of Trade of the Casa de Contratacíon (Council of the Indies) oversaw all operations of the flota (treasure fleet). They controlled every aspect of the ships from the men who crewed them, to the armament aboard, to the cargo and passengers carried. From 1550 to 1735, the flota crisscrossed the Atlantic, bringing supplies and people from Spain to the New World and returning home laden with silver, gold, emeralds, pearls, silks, indigo, and spices.
Initially, merchant ships sailed between Spain and the New World alone, but frequent pirate attacks that caused heavy losses changed this. An armed convoy of ships was introduced, and once the galleons became part of the flota, the Council of the Indies reorganized the system once again. After 1564 two fleets sailed. The Tierra Firme Flota usually departed Seville in August, bound for Cartagena and Panama. The New Spain Flota sailed in April for Vera Cruz. Each voyage usually took two to three months, and the ships rarely departed on schedule. Both wintered in the New World, then joined up in Havana around February or March. Laden with their precious cargoes, the combined flota sailed for Spain. Sometimes, however, each returned to Spain separately.
Pirates continued to attack the treasure ships, so the Council of the Indies added a third convoy to the flota system in 1591, a change which remained in effect until the mid 1600s. Comprised of up to twelve galleons and at least two pataches (dispatch boats), the Armada de Tierra Firme carried only treasure. The average weight of the Silver Fleet galleons was six hundred tons, but some weighed one thousand tons. Each galleon carried two hundred marines and much armament to safeguard the cargo against pirate attacks.
