In Roman times Teutonic speech was thus most characteristic of the belt outside the Rhine frontier of the Roman Empire, and from this basis we may trace the Teutonic peoples onwards. The forests of Germany were dense and extensive, and apparently in post-Roman times they were being attacked in two ways: the hill people were moving down and making the population more Alpine in physical type and more Alemannic in language, and the Church was founding abbeys and spreading its influence across the Rhine from the erstwhile Roman frontier-cities then becoming cities of the Roman Church in most cases. The wave of Roman civilization interrupted by the barbarian movements was thus resumed under Church leadership, and with it went the growth of towns and of intercourse, after some time making the contrast between south and north in Germany not only a contrast between hills and plains and between High German and Low German, but also a contrast between a much more Romanized and civic south and a much less Romanized and more rural north, though the Church did establish itself in the north in due course. Alemannic became characteristic of the hill belt next beyond the region of French speech, and there replaced a Brythonic Celtic language. But farther east the languages of the hill people had by this time taken Slavonic form, so that the Alemannic belt was of but moderate width, including the Alps and their northern flanks down to the Prussian plain, but not Bohemia and the Carpathian arc which were of Slavonic speech (p. 61). The downhill movement above mentioned characterized the Slavonic hill lands as well as the Alemannic, so that on the Prussian plain east of the Elbe old languages (probably of Lettic kinship, see p. 18) gave way to Slavonic, and in course of time the Elbe became the {40} frontier between German and Slavonic, with the Altmark (old frontier territory) to the west of it.