The first means adopted by the northern maritime nations to appropriate to themselves a share of the riches of the New World was open, semi-piratical attack upon the Spanish argosies returning from those distant El Dorados. The success of the Norman and Breton corsairs, for it was the French, not the English, who started the game, gradually forced upon the Spaniards, as a means of protection, the establishment of great merchant fleets sailing periodically at long intervals and accompanied by powerful convoys. During the first half of the sixteenth century any ship which had fulfilled the conditions required for engaging in American commerce was allowed to depart alone and at any time of the year. From about 1526, however, merchant vessels were ordered to sail together, and by a _cedula_ of July 1561, the system of fleets was made permanent and obligatory. This decree prohibited any ship from sailing alone to America from Cadiz or San Lucar on pain of forfeiture of ship and cargo.[12] Two fleets were organized each year, one for Terra Firma going to Cartagena and Porto Bello, the other designed for the port of San Juan d'Ulloa (Vera Cruz) in New Spain. The latter, called the Flota, was commanded by an "almirante," and sailed for Mexico in the early summer so as to avoid the hurricane season and the "northers" of the Mexican Gulf. The former was usually called the galeones (_anglice_ "galleons"), was commanded by a "general," and sailed from Spain earlier in the year, between January and March. If it departed in March, it usually wintered at Havana and returned with the Flota in the following spring. Sometimes the two fleets sailed together and separated at Guadaloupe, Deseada or another of the Leeward Islands.[13] The galleons generally consisted of from five to eight war-vessels carrying from forty to fifty guns, together with several smaller, faster boats called "pataches," and a fleet of merchantmen varying in number in different years. In the time of Philip II. often as many as forty ships supplied Cartagena and Porto Bello, but in succeeding reigns, although the population of the Indies was rapidly increasing, American commerce fell off so sadly that eight or ten were sufficient for all the trade of South and Central America. The general of the galleons, on his departure, received from the Council of the Indies three sealed packets. The first, opened at the Canaries, contained the name of the island in the West Indies at which the fleet was first to call. The second was unsealed after the galleons arrived at Cartagena, and contained instructions for the fleet to return in the same year or to winter in America. In the third, left unopened until the fleet had emerged from the Bahama Channel on the homeward voyage, were orders for the route to the Azores and the islands they should touch in passing, usually Corvo and Flores or Santa Maria.[14]