Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)We study algebraic geometry codes producing quantum error-correcting codes by the CSS construction. We pay particular attention to the family of Castle codes. We show that many of the examples known in the literature in fact belong to this family of codes. We systematize these constructions by showing the common theory that underlies all of them.151040714088Spanish Ministerio de Economia y Competitividad Grant MINECO/FEDER [MTM2015-65764-C3-1-P]CNPq, Brazil [201584/2015-8, 308326/2014-8]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)