This article undertakes the palaeographic study of documents written by the wives of Manuel I of Portugal, Isabel and María. It examines the alphabet, links, abbreviations, special symbols, forms of correction and validation used by the queens in their autographed documents, and their signatures on original chancery documents. Using the data contained in the accounts of Gonzalo de Baeza, treasurer to the Catholic Queen Isabel I of Castile, and those, as yet unpublished, of Ochoa de Isasaga, treasurer to Queen María, it studies their early education, the writing instruments they used and the books contained in their personal libraries.