At this point the focus of his research had not yet been drawn on the Maya script. This would change in 1947, when at the instigation of his professor, Knorozov wrote his dissertation on the "de Landa alphabet", a record produced by the 16th century Spanish Bishop Diego de Landa in which he claimed to have transliterated the Spanish alphabet into corresponding Maya hieroglyphs, based on input from Maya informants. De Landa, who during his posting to Yucatán had overseen the destruction of all the codices from the Maya civilization he could find, reproduced his alphabet in a work ("Relación de las Cosas de Yucatán") intended to justify his actions once he had been placed on trial when recalled to Spain. The original document had disappeared, and this work was unknown until 1862 when an abridged copy was discovered in the archives of the Spanish Royal Academy by the French scholar, Charles Étienne Brasseur de Bourbourg.