BOLESLAUS III., king of Poland (1086-1139), the son of Wladislaus I. and Judith of Bohemia, was born on the 23rd of December 1086 and succeeded his father in 1102. His earlier years were troubled continually by the intrigues of his natural half-brother Zbigniew, who till he was imprisoned and blinded involved Boleslaus in frequent contests with Bohemia and the emperor Henry V. The first of the German wars began in 1109, when Henry, materially assisted by the Bohemians, invaded Silesia. It was mainly a war of sieges, Henry sitting down before Lubusz, Glogau and Breslau, all of which he failed to take. The Poles avoided an encounter in the open field, but harried the Germans so successfully around Breslau that the plain was covered with corpses, which Henry had to leave to the dogs on his disastrous retreat; hence the scene of the action was known as "the field of dogs." The chief political result of this disaster was the complete independence of Poland for the next quarter of a century. It was during this respite that Boleslaus devoted himself to the main business of his life - the subjugation of Pomerania (i.e. the maritime province) with the view of gaining access to the sea. Pomerania, protected on the south by virgin forests and almost impenetrable morasses, was in those days inhabited by a valiant and savage Slavonic race akin to the Wends, who clung to paganism with unconquerable obstinacy. The possession of a seaboard enabled them to maintain fleets and build relatively large towns such as Stettin and Kolberg, whilst they ravaged at will the territories of their southern neighbours the Poles. In self-defence Boleslaus was obliged to subdue them. The struggle began in 1109, when Boleslaus inflicted a terrible defeat on the Pomeranians at Nackel which compelled their temporary submission. In 1120-1124 the rebellion of his vassal Prince Warceslaus of Stettin again brought Boleslaus into the country, but the resistance was as stout as ever, and only after 18,000 of his followers had fallen and 8000 more had been expatriated did Warceslaus submit to his conqueror. The obstinacy of the resistance convinced Boleslaus that Pomerania must be christianized before it could be completely subdued; and this important work was partially accomplished by St Otto, bishop of Bamberg, an old friend of Boleslaus's father, who knew the Slavonic languages. In 1124 the southern portions of the land were converted by St Otto, but it was only under the threat of extermination if they persisted in their evil ways that the people of Stettin accepted the faith in the following year. In 1128, at the council of Usedom, St Otto appointed his disciple Boniface bishop of Julin, the first Pomeranian diocese, and the foundation of a better order of things was laid. In his later years Boleslaus waged an unsuccessful war with Hungary and Bohemia, and was forced to claim the mediation of the emperor Lothair, to whom he did homage for Pomerania and Rügen at the diet of Merseburg in 1135. He died in 1139.
See Gallus, Chronicon, ed. Finkal (Cracow, 1899); Maksymilian Gumplowicz, Zur Geschichte Polens im Mittelalter (Innsbruck, 1898).
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)