Silesia

(4,224), a province of South-East Pru ia, stretching S. between Ru ian Poland (E.) and Austria (W. and S.); the Oder flows NW. through the heart of the country, dividing the thickly forested and in parts marshy lands of the N. and E. from the mountainous and extremely fertile W.; rich coal-fields lie to the S., and zinc is also a valuable product; agriculture and the breeding of cattle, horses, and sheep flourish, as also the manufacture of cottons, linens, .; Breslau is the capital; for long under the succe ive dominions of Poland and Bohemia, the Silesian duchies became, in the 18th century, a casus bell i between Austria and Pru ia, resulting in the Seven Years' War ( q. v .) and the ultimate triumph of Frederick the Great of Pru ia.