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Hematoxylin is a basic dye derived from the heartwood of Palo de Campeche ( Haematoxylum campechianum), the logwood tree native to Mexico and Central America. Haematoxylum means "bloodwood" in reference to its dark-red heartwood and campechianum refers to its site of origin, the coastal city of Campeche on the Yucatan Peninsula, Mexico. Hematoxylin is colorless but it turns into the color dye hematein after oxidation (ripening). The dyeing property of logwood was well-known to the natives of the Yucatan Peninsula before the arrival of the Spaniards who brought it to Europe shortly after the discovery of the Americas. An important trade soon developed related to growing and preparing hematoxylin for dyeing fabrics. Pirates discovered that one shipload of logwood was equivalent to a year's value from any other cargo, and by 1563, more than 400 pirate vessels wandered the Atlantic Ocean and attacked Spanish galleons transporting gold, silver, and logwood from the Americas to Europe. Hematoxylin and eosin is a staining method that dates back to the late 19th century. In 1865 and 1891, Böhmer and Meyer, respectively, first used hematoxylin in combination with a mordant (alum). Later, with the use of anilines by Ehrlich, the repertoire of stains expanded rapidly resulting in the microscopic descriptions of multiple diseases that were defined by their stainable features. Today hematoxylin, along with eosin, remains the most popular stain in histology.