This thesis deals with the analysis of Rovinj's first names read from the Rovinj's registers of baptisms and births, starting with those names enrolled in 1560 (when the oldest preserved baptismal record in the Rovinj area dates) until the end of the 20th century, more precisely until 1983. This paper is devided into twelve chapters. The introductory chapter contains several subchapters. The initial subchapters explain the topic of the thesis and define the area and methodology of the research. The following subchapter is about registry books, in which is discussed the importance of those books for onomastic research. Next, in a separate subchapter, important historical, geographical, demographic, socio-cultural and linguistic aspects of Rovinj and the Rovinj region are presented. After that follows a summary of previous onomastic research in Istria. The second chapter is devoted to topics concerning onomastic theories—a name is defined as a linguistic and onomastic sign: this chapter deals with some theories about names, discusses the relationship between name and appellative and briefly outlines the basic functions of the name. The third chapter deals with the first name. After the definition and presentation of the relationship between the first name and (proper) name, an overview of the origin, development, and formation of the first name system in Croatia is given, as well as a review of the legal regulations considering the process of naming a person. The following chapter is about sources and corpus, followed by a chapter questioning the principles of stuffing and the level of heredity of Rovinj's first names. The sixth, seventh and eighth chapters, through numerous subchapters, describe in detail the structure, linguistic features and frequency of Rovinj's first names. Those chapters exhaustively analyze Rovinj's first names by showing their frequency, describing their structure, and questioning the principles of naming and linguistic aspects. Since most of the listed names are first names written in Italian (Venetian idiom), this thesis explains at the grapheme level, based on linguistic knowledge of the theory of language in contact, the adaptation of the Croatian phonological system to such Italian graphics. Quantitative analysis showed that in the observed years, boys were most often given the names Zuanne, Antonio, Francesco, Iseppo and Domenico, and to girls Eufemia, Domenica, Antonia, Cattarina and Francesca. It has also been shown that only the first names Zuanne, Antonio, Antonia and Cattarina appear in all the observed years throughout the studied four-hundred-year period. Considering the number of components in the analyzed corpus, single (both male and female) first names dominate, and regarding the likely impetus for the choice of name, it turned out that the hereditary principle is more represented than the calendar. The analysis is supplemented by numerous tabular representations and graphs, which contribute to the clarity of the obtained results. Using literature related to the Rovinj area, we tried to see if there was a connection between the social status of individual families (Rovinj history knows about fifteen noble families) and the choice of first names of members of these families. The concluding, ninth chapter presents the cognitions derived from the analysis of first names; it is concluded that the dominant characteristics of first names of baptized/born children in Rovinj are: naming children with single (one-word) first names chosen primarily by applying the hereditary principle. This paper also demonstrates that first names are sociolinguistic signs in which the linguistic and extralinguistic reality are reflected in a specific way. This thesis ends with a bibliographic list divided into sources and literature, a list of abbreviations, tables, graphs and figures, as well as the author's biography and a list of published works. The analysis of the first name corpus has been supplemented, for a better understanding and insight into the name and naming system of the Rovinj region, with a list of a representative first name corpus excerpted from the Rovinj registers of baptisms and births.