ENThe history of formulaic language in historical texts is receiving increasing attention in recent phraseology research. In the article, the diplomatic letters from the chancellery of the Lithuanian Grand Duke Vytautas Magnus (14th–15th centuries) are analysed in terms of their formulaic character. The royal letters reflect the development of the administrative language in the Grand Duchy of Lithuania and show a strong influence of ancient and medieval letter traditions. The formulaic character of diplomatic letters can also be characterized as an important characteristic of political terminology. The conducted study shows the variation of the formulaic expressions in the royal letters by determining the variant models and describing their syntactic and/or semantic properties. The usual formulas that are characteristic of this type of text are illustrated with evidence from the introductory part of the letter salutatio. The history of formulaic language in historical texts is receiving increasing attention in recent phraseology research. In the article, the diplomatic letters from the chancellery of the Lithuanian Grand Duke Vytautas Magnus (14th–15th centuries) are analysed in terms of their formulaic character. The royal letters reflect the development of the administrative language in the Grand Duchy of Lithuania and show a strong influence of ancient and medieval letter traditions. The formulaic character of diplomatic letters can also be characterized as an important charac-teristic of political terminology. The conducted study shows the variation of the formulaic expressions in the royal letters by determining the variant models and describing their syntactic and/or semantic properties. The usual formulas that are characteristic of this type of text are illustrated with evidence from the introductory part of the letter salutatio.