Yiddish is, since Max Weinreich's fundamental work (Weinreich 1973, 1980), referred to as a fusion language in which components of different languages form a comprehensive synthesis. As Yiddish arose in early Ashkenazic communities in German speaking territories from the 10th century onwards, German contributes the most to its component multiplicity. From the start, some Hebrew-Aramaic and Romance elements inherited from the pre-German period were incorporated in the Yiddish language and remained along with the Hebrew script – though Yiddish to this day clearly bears the marks of its genetic origin as a West-Germanic language. The migration of a large number of Jews to Eastern Europe after the pogroms of the 13th and 14th centuries gave way to an enormous influence of the Slavic speaking environment on the rising Eastern Yiddish (as opposed to Western Yiddish, being the variety of the language that was retained on German speaking territory) and hence added a fourth component. In response to the emancipation, Yiddish lost ground in the Western sphere and substantially disappeared in Germany at the end of the 18th century, whereas in Eastern Europe, the number of Yiddish speakers increased rapidly, and gradually the language became regionally differentiated. The pre-war Eastern Yiddish speaking territory may be divided as follows: Northeastern Yiddish (Lithuania, Latvia and Belorussia), Southeastern Yiddish (Ukraine, Rumania and Eastern Galicia) and Central Yiddish (Poland and Western Galicia). The great migratory movements at the turn of the century spread the Yiddish language to the far corners of the earth, with several vernaculars being the source of a fifth component. The persecutions and the genocide through the Nazi-regime led to the annihilation of a vast number of Yiddish speakers, all but completely destroying the language in its historical territory and giving proportionally more importance to the rapidly evolving varieties of the new emigration countries.