In 1572, Drake embarked on his first major independent enterprise. He planned an attack on the Isthmus of Panama, known to the Spanish as Tierra Firme and the English as the Spanish Main. This was the point at which the silver and gold treasure of Peru had to be landed and sent overland to the Caribbean Sea, where galleons from Spain would pick it up at the town of Nombre de Dios. Drake left Plymouth on 24 May 1572, with a crew of 73 men in two small vessels, the "Pascha" (70 tons) and the "Swan" (25 tons), to capture Nombre de Dios.