In the chapter "Iranian and Slavic" there are analyzed 40 Slavic lexemes attested in South or West Slavic languages. For these lexemes it is possible to propose borrowing still before the Slavic disintegration (6th cent. CE) from several Iranian donor-languages. With respect to historical context and on the basis of sound rules established for the Iranian languages the following four chronological layers of borrowing may be determined: A. Common Iranian / pre-Avestan (around 1200 BCE); B. Sakish (before 500 BCE); C. Sarmatian (first half of the 1st mill. CE); D. Parthian - Middle Persian (first half of the 1st mill. CE).