The article introduces two internet sources designated to the study of Older Czech language (13th to 18th centuries); both have been designed and run by The Department of Language Development at The Institute of the Czech Language at the Academy of Sciences of the Czech Republic. The first source, Vokabulář webový [Web Vocabulary] (http://vokabular.ujc.cas.cz), makes texts, images and audio materials available to the study of Older Czech language. The accessible materials are, primarily, both modern and historical dictionaries, amongst which the most salient is the, gradually growing, Elektronický slovník staré češtiny [Electronic Old-Czech Vocabulary] that treats Old-Czech lexicon from the dawn of Czech language to the end of the 15th century. Furthermore, Vokabulář includes electronic editions of the works originating in the period from the 13th century to the beginning of the 19th century, presented both as continuous texts and in the corpus version; digitalized copies of Older-Czech grammar books; basic scientific literature; audiobooks of Older-Czech texts; and software tools utilized for the work with historical texts. The second source is Lexikální databáze hu-manistické a barokní češtiny [Lexical Database of Humanistic and Baroque Czech] (http://madla.ujc.cas.cz). It records the Czech vocabulary of the 16th to 18th centuries based on the excerption of the authentic contemporary texts (both old prints and manuscripts): Lexical database illustrates the Czech vocabulary with direct quotations, including stating the source. Thus, Lexical Database partly substitutes the missing Czech vocabulary of the mentioned period.