UNTIL recently no purely method existed for objectively gauging the antiquity of language divergence. Hence, in her coordination of archeological cultures and prehistoric groups, Marija Gimbutas (1952) had at her disposal only relative chronologies except insofar as scholars had previously attempted to do what she did, that is, to associate divergences with movements of people and to assign dates to them on the basis of archeological evidence. most specific evidence for connecting given prehistoric stages of languages with definite archeological cultures is that of linguistic paleontology. Thus, historic languages like Latin, Teutonic, Church Slavic, Greek, Persian, Sanskrit, which are differentiated late continuations of a single ancient prehistoric tongue known as Indo-European, have related words for various agricultural concepts. From this it follows that the prehistoric Indo-Europeans already practised agriculture and raised domestic animals before they separated and scattered. As Gimbutas points out, The main surviving names of the common speech point to a neolithic stage of development; no certain word for any metal survived (p. 606). For relatively recent prehistoric periods, important additional evidence may be obtained from place names; just as the toponymy of modern America includes a certain number of geographic names from the Indian languages, so too the map of Europe contains vestiges pointing to the tongues spoken in each area prior to the earliest known history. To these lines of evidence we can now add that of lexico-statistic dating, based on the recently discovered fact that the every-day, non-cultural vocabulary tends to be replaced at an approximately constant rate (Swadesh 1952). Wherever an ancient speech community has broken up, either because of migration or the weakening of such ties as intermarriage, common ceremonial events, trade, travel, etc., the changes in one area become more or less independent of those taking place elsewhere. From the percentage of cognate words still present in two test vocabularies, we can therefore obtain an index of the time period during which the two languages have been diverging. While much research still needs to be done before this method can be improved to its maximum of potential accuracy, it has already proved approximately correct in a series of cases where it was possible to check it against historical and archeological knowledge. Such instances, to which North Indo-European can now be added, include: