The article examines the origin and meaning of 10 Christian names: Avreliya, Akulina, Anesti, Ventseslav, Evlaliya, Zheneva, Melaniya, Serafim, Sozont, and Fotiniya. They have entered Bulgaria in different times in different ways and circumstances. All of them, with the exception of Ventseslav, are incomprehensible to Bulgarians and contain some phonemes and combinations of phonemes that are unusual for the Bulgarian language. Their adapting to Bulgarian phonetics, morphology, and semantics has manifested itself in different ways at various locations — depending on the particularities of local dialects. Based on these 10 names, 50 new first names have come into existence that are used independently from the basic ones. Some of the analyzed names indicate a relationship with Russian Old Believers (Akulina and var., Sazon, Sozon; Vyacheslav), others with Bulgarian Catholics (Ventseslav, Evlaliya, some var. of Serafim), with the Walachians (Avreliya), Greeks (Anesti, Fotini), or Czechs and Slovaks (Ventseslav). The special semantics of the personal proper names and, in some cases, their similarity in shape (homonymy) with some common nouns, impede the analysis. Sometimes resolving ambiguity is almost impossible without the help of extralinguistic information that may be obtained only through interview or inquiry.