This paper presents a literary-historical and philological analysis of the work Adrijanskoga mora sirena written by Petar Zrinski. It is a baroque epic that is structurally and substantially based on the Hungarian epic Adriai tengernek Syrenaia by Nikola Zrinski and is considered to be its adaptation. This paper starts by talking about the political and cultural environment Petar Zrinski was surrounded by and in which he worked. Starting from his childhood to the most significant military contributions in the Thirty Years' War and later in the conspiracy against The Habsburgs, Zrinski had great military and political experiences that he later used wisely as arguments in the Siren. In writing the epic he used his theological-scientific education and literary formation, but also in his philosophical work and linguistic efforts to expand the language formed by the literary circle based in Ozalj in which he operated. All this has influenced the creation of the Siren and it leads to the central part of this paper which is based solely on the analysis of the whole epic. The analysis is based on multiple levels: content, style, structure, ideology and linguistics, and each of them are individually elaborated. The last part of this paper discusses the differences between Hungarian and Croatian version of the epic and these differences are based on the fact that the work is not a translation of the epic but an adaptation where as a very important aspect comes in light the creativity and originality of the author.