LADRILLEROS, Juan (lah-dreel-yair'-oth), Spanish navigator. He lived in the 16th century, and took an active part in the civil wars of Peru. He was ordered by Garcia Hurtado de Mendoza (q. v.) to examine the southern coast of that country and the Strait of Magellan, and left Valdivia in November, 1557, with two vessels. After many adventures, and an attempt at a mutiny by the crew, he succeeded finally in entering the strait, minutely examined the neighboring coast, and returned to Valdivia with a single sailor and a negro. The result of his voyage was a more exact knowledge of the island of Chiloe and the neighboring groups. There are two manuscript copies of his journal preserved in the general archives of the Indies. Navarrete has inserted the narrative of Ladrilleros in the introduction to his "Relacion del dltimo viage al estrecho de Magallanes en los afios de 1785 y 1786" (Madrid, 1788). The voyage of Ladrilleros was the first to overturn the opinion that it was impossible to return by the Strait of Magellan from the Pacific to the Atlantic.