In 1517 he sent Juan de Grijalva to explore the coast of Mexico and in 1518 he sent Francisco Hernández de Córdoba to explore the coast of Yucatán. Then in 1519 he sent his secretary, Hernán Cortés, to conquer Mexico with about 450 soldiers but when Cortés got to México (in Veracruz), he broke all relations with Velázquez.