he demand for Baroque music on the concert stage sets high requirements for singers in terms of the performance style. At present, the issues of reproducing vocal ornamentation in ancient arias are the primary tasks. Given the lack of knowledge and skills of baroque improvisation among Russian singers, the ornamentation used often represents, in fact, only a technical aspect that the soloists are diligently trying to cope with. At the same time, ornaments often sound "empty", not expressive, not corresponding to the main purpose which is to emphasise affect. According to the instructions of the 17th century masters, the main purpose of performing music was to show the passions of the human soul. The singers’ fundamental task was to maximise the impact on the listener’s feelings and to awake affects in them through an intoned word. As a vivid expressive means, ornamentation contributed to the emphasis of certain words in the general context. Moreover, according to the instructions of teachers from the past, singers needed to convey one or another affect with the appropriate intonation of the voice. The artistic function of ornaments came down to increasing the level of performance expressiveness. Various ornamentation (melismas and passages) had to be used purely to enhance the musical statement. The proposed article is aimed at solving actual problems in the field of Baroque performance, problems related to the correct interpretation and performance of vocal ornaments in 17th century works. The historicism principle is the methodological basis of the work. Using the methods of analysis and synthesis, as well as the cultural and historical method of research, the author managed to recreate the historical significance of the ornament in connection with the opera traditions of the 17th century. The author's position is that for a singer, it is important to understand the figurative and expressive functions of any type of ornamentation (melismas, passages) as one of the main means of expression, contributing to revealing the composition affect, which presents scientific novelty and is the main conclusion of the article. The content and conclusions of the article will be useful to musicians, singers performing 17th century compositions for their stylistically correct interpretation, as well as in training courses on the history of vocal performance and stylistics at Performing Arts departments of music colleges and university faculties.