The article discusses the features of the formation of the lexical-semantic group "Fortitude (Courage) " in the English and Spanish languages of the XIII-XV centuries, an important role in the formation of which was played by extralinguistic, in particular, religious factors. The source of the research material in English is presented by manuscripts of the XIII-XV centuries contained in the Corpus of Middle English Prose and Verse. The source of the research material in Spanish is presented by manuscripts of the XIII-XV centuries contained in the electronic corpus of the Corpus del español. The lexemes of this group in the languages under study belonged to the core of the lexis of positive moral and ethical evaluation in the period under review. This is explained by the significant role of the Church in the formation of ethical norms in mediaeval society. Mediaeval authors singled out seven virtues, three of which were considered theological (Faith, Hope, Love), and the remaining four were called cardinal: Prudence, Justice, Purity, and Fortitude (Courage). The names of virtues became semantic centers around which lexis of positive moral and ethical evaluation was formed in the English and Spanish languages of the XIII-XV centuries.