OE'SEL, an island of Russia, in the Baltic, belonging to the government of Livonia, and lying across the mouth of the gulf of Riga. It is about 80 in. in length from n.e. to s.w., and about 40 m. in greatest breadth, but the s.w. end consists of a comparatively narrow peninsula. A narrow strait separates the n.e. end from the island of Dago. The surface is undulating, broken by low hills, marshy, watered by numerous small streams, and well wooded. The coast is generally formed by high cliffs. The climate is milder than that of the neighboring continental districts. The rocks are generally calcareous, and the soil is in many places gravelly; the chief crops are wheat, oats, rye, barley, and pease. The rearing of cattle, horses, and sheep, mid fishing, are, however, i the principal occupations of the inhabitants. The seal-fisheries are of some importance. Pop. 46.000, mostly Lutheran, The only- town is Arensburg, on the s,e. coast, with a
pop. (1867) of 3,256. Many of the inhabitants of Arensburg are of German descent, as are the nobles and clergy of the island; but the peasantry are Esthonian. The islanders of Oesel were in early times noted as pirates. The Danish king Waldemar conquered the island in the beginning of the 13th century. Albert von Buxhiivden, bishop of Leal in Livonia, obtained it from Denmark in 1227, in order that he might reduce its inhabi tants to subjection• and convert them to Christianity. Being partly subdued by the Teutonic knights, it remained for more than 300 years under its bishops, the seat of the bishopric being transferred to the island. The last bishop sold it to Denmark in 1559. It remained a Danish province till 1645, when it was given up to Sweden, and in 17.'a fell into the hands of Russia.