In 1514, Velázquez wrote to the king concerning rumors of unknown lands to the north and west of Cuba. Initially, these rumors were merely the subject of idle speculation and the king instructed Velázquez to remain focused on the governance of Cuba and especially the production of gold. However, as the demand for labor grew, slaving expeditions explored the region in search of natives to work the Cuban ranches and gold mines. Interest in exploration and conquest intensified in 1516 when a slave ship returned carrying 20,000 pesos of gold seized from the natives living on the Guanajes, a series of small islands off the coast of Central America.