In western and northern Bohemia a struggle for supremacy between German and Czech has been carried on for years with unabated vehemence. The scene of contest between the two peoples is often laid in individual communes. Clerical, industrial and educational influences are constantly at work for the extension of the linguistic area with which they side. On the whole the Bohemians, being in command of superior pecuniary resources, appear to be gaining ground, although from special causes the German element shows an advance in certain districts. In those parts where mixture has taken place no definite boundary between pure German and Bohemian (i.e., in over 90 per cent of the respective peoples) can be drawn. As a rule, it is the Bohemians who have of late advanced their outposts into the German sphere, the Germanization of which dates back some two hundred years. Although they have fallen back somewhat in the tongue of land which projected into German ground, north of Mies, they have gained much ground in Pilsen and in the industrial region around Nürschan, west of that town. Fifty years ago only some three or four thousand out of a total population of fourteen thousand in Pilsen were Bohemians, but the influx of population which has since taken place has been almost entirely Bohemian. In 1890 the proportion of Germans in the city only amounted to 16.2 per cent. Nürschan, the chief center of the coal-fields of western Bohemia, boasts a Bohemian majority and if the process now going on is continued the Bohemian population will probably in time join hands with that in Mies.[148] Further to the northeast similar conditions prevail, though the linguistic frontier is in parts more sharply defined. In the coal-fields of Brüx and Dux the Bohemian element has largely increased on the German side of the normal frontier owing to the influx of Czech miners. In Trebnitz again the Czech language has gained a firm footing, although the town at the end of the nineteenth century was entirely German. In the neighboring town of Lobositz, however, which occupies an important position at the junction of six lines of railway, the prospects from the German point of view are brighter. The accession of Charles IV to the throne of Bohemia in 1346 was an event of the utmost importance in the linguistic history of the country.[149] This sovereign, the successor of German princes who had never allowed Bohemia fair play, showed marked affection for the land he was called upon to rule and set himself to master its language thoroughly. For two hundred years prior to his reign, Bohemian stood in danger of being replaced by German. Other Slav dialects were fast disappearing before the vigorous advance of Teutonic speech. Through its literature alone the Bohemian language was preserved. This literary development was an advantage which was not possessed by the Slav languages, which gave way before German.