The slopes of the Sudetes are covered with fine pine forests and here we have manufactures dependent on a good supply of wood; e.g., paper, toys and matches. The plain, with its soft rocks, is supplied with building material from the quarries of the Sudetes. Above the tree line are the summer pastures of large herds of cattle. It is only the smaller share of the great industrial region of the south-east that has remained to Germany, but Silesia is still important for its coal mines, and its iron-, lead and zinc-smelting works. Along the Sudetes at various places there are mineral springs.
The main line of communication is the railway that runs from Sagan via Liegnitz and Breslau to Oppeln, where it branches, sending one arm to Beuthen in the industrial south-east, and the other via Ratibor, the upper Oder and the March valleys towards Vienna. This main line throws off a number of branches north eastward to Poland. Another line runs roughly parallel to it from Hoyerswerden to Ratibor passing through a number of industrial towns. It is linked with the main line at numerous points. The Sudetes are crossed by three important railways, from Gorlitz, from Waldenburg and from Glatz. The Oder is navigable nearly throughout the province, i.e., from Kosel, whence the Klodnitz canal enables barges to tap the industrial region around Gleiwitz and Hindenburg. The bigger cities in the plains have varied manu factures, and Breslau is the commercial as well as the political capital. For administrative purposes the province is divided into 14 city and 57 rural circles.
Early Period.—From the evidence of place-names, it ap pears as though the population of Silesia was at one time Celtic ; but when its historical records begin with its incorporation into the new kingdom of Poland (c. A.D. i000), we find it populated by Slavonic tribes, one of which, deriving its name from the mountain Zlenz, gave Silesia its name. On the death of Boleslaw III. of Poland (I138), his dominions were partitioned, and Silesia was constituted a separate principality, which in 1163 was divided into the ducatus Zlesie and the ducatus Opoliensis, these again disintegrating during the succeeding centuries into ever smaller units. By the end of the 14th century, Silesia consisted of 18 principalities: Breslau, Brieg, Glogau, Jauer, Liegnitz, Miinsterberg, Oels, Schweidnitz and Steinau in Lower Silesia; Beuthen, Falkenberg, Kosel, Neisse, Oppeln, Ratibor, Strehlitz, Teschen and Troppau in the upper district. As members of the Piast house and principes Poloniae, the Silesian dukes remained ,outside the German empire ; but as from the first they adopted the policy of inviting German settlers to fill their vacant land, and founding towns which enjoyed German law, their lands soon became virtually German. The result was much material pros perity; forest and swamp lands were reclaimed ; the weaving and mining industries acquired great importance and Breslau (which was refounded c. 1250 as a German town) became a large mar ket for the wares of the East and the West.
At the beginning of the 14th century the Silesian dukes ex changed their nominal allegiance to Poland for allegiance to Bo hemia, becoming members of the Empire; and as some of the Piast dynasties died out, their lands were appropriated as crown land by the Kings of Bohemia. The earlier Bohemian overlords justified their intrusion by their vigorous administrative and other reforms; the cities in particular enjoyed greatly increased ma terial prosperity and political importance. Later, however, the Bohemian connection involved Silesia in the Hussite wars. In
142o Silesia supported Sigismund against the Bohemian rebels, whom it regarded as dangerous to the German nationality, but suffered in consequence a series of devastating invasions (1425– 35) which permanently weakened the German element. Had the Hussite, George Podiebrad, who was accepted by most of the Silesian dynasties, but fiercely repudiated by the burghers of Breslau, retained the Bohemian throne which he mounted in the Slavonic element might have regained the upper hand ; but he was replaced by Matthias Corvinus, whom Silesia readily recog nised as overlord. Corvinus' reforms, although effective, were financially exacting, and under his successor Vladislav the Silesians exacted concessions which gave them virtual autonomy.
The estates of Silesia accepted the accession of Ferdinand I. of Habsburg without demur (Dec. 5, 1526), but under their new dynasty they soon lost almost all their old rights, and the land gradually passed to the Crown as the old dynasties became extinct. After an uneventful period, the land was almost ruined by the Thirty Years' War (1618-48) in which Silesia, which was almost wholly Protestant, had joined with the rebellious Bohemians. It was punished less severely than Bohemia, but for years was the battlefield of contending armies, and overrun by lawless mer cenaries. Three quarters of the population lost their lives, and trade and industry were brought to a standstill. Owing to the permanent diversion of trade routes, and the disregard by the Habsburgs of their undertakings towards their Protestant sub jects, recovery was slow, although the representatives of Charles XII. of Sweden secured for the Silesians some religious liberty, and the emperor Charles VI. tried to stimulate trade with Austria.
In 1740 Frederick II. of Prussia laid claim to the former Duchies of Liegnitz, Brieg, Jagerndorf and Wohlau, on the strength of a testamentary disposition made in 1537 and later annulled. He oc cupied Lower Silesia, which Maria Theresa was forced to yield him in 1741, and in 1742 extorted from Austria the whole re mainder of Silesia except the districts of Troppau, Teschen and Jagerndorf. Maria Theresa's tenacious endeavour to recover her lost province proved unsuccessful, although in the Seven Years' War (q.v.) she was near success.