283 Poland in the eleventh and twelfth centuries 
of  Germany,  who started  a  military  expedition  against  Poland in  1109.Yet 
Boleslaw Krzywousty’s military skills, his skilful appealing to patriotic moods, 
together with his alliance with Ruthenia, based on his marriage with Zbyslawa, 
daughter  of  the  prince  of  Kiev,  and  a  temporary  alliance  with  Hungary, 
which involved a diversionary raid on Bohemia, provided Poland with sup-
port. The determined defence of Glogow, the serious defeat of the German 
troops  in  the  battle  of  Psie  Pole  near  Wroclaw  and  the  defiant  attitude  of 
Boleslaw, who would not give up under Henry V’s threat of marching toward 
Cracow, the capital at the time, contributed to the failure of the expedition. 
Three years later Boleslaw allowed his brother to return, but, on the pretext 
of his arrival having been too ostentatious, had him blinded, thus causing his 
death. 
Despite Boleslaw’s family ties through his mother with the Czech dynasty 
of Przemyslids, his relations with Bohemia were tense. This was due to the 
Czech attempts to win control over the Silesian frontier castle-towns (Racib
´
orz, 
Kozle, Kamieniec), to Bohemia’s continuing vassal dependence on Germany, 
with which Boleslaw was at war, and finally to Boleslaw’s attempt to interfere 
in the disputes over the Bohemian throne. These conflicts ceased in 1114 and 
the peace treaty with Bohemia was made in 1137. 
The  question  of  Pomerania  took  priority  in  Boleslaw  Krzywousty’s  pol-
icy.  By  1106  he had already led  several  plundering raids into  this  province, 
which Zbigniew must have been trying to hinder. After Zbigniew’s banish-
ment, he  launched  the plan  of  the conquest of  Pomerania. In 1113  he  won 
definite control of the frontier castle-towns, Naklo and Wyszogrod; by 1119 
he had subjugated Gdansk-Pomerania (Pommerellen), and he then conquered 
western Pomerania, reaching R
¨
ugen (Rugia) in 1123.In 1121 he imposed feudal 
overlordship over Prince Warcislaw of  western Pomerania; in 1124  he  eased 
the rigorous conditions of this suzerainty. Boleslaw Krzywousty’s undeniable 
success was the second Christianization of Pomerania. The earlier attempts by 
Poland in the late tenth century had no lasting effect, and the bishopric of 
Kolobrzeg (Kolberg), founded in the year 1000, disappeared. The missionary 
efforts of the hermit Bernard the Spaniard in 1123 did not succeed. The next 
attempt was made under Boleslaw’s auspices by Bishop Otto of Bamberg. His 
success encouraged him to form a new missionary expedition, which he led on 
his own behalf in 1128. The posthumous achievement of Boleslaw Krzywousty 
was the  fact  that his  chaplain  Wojciech  (Adalbert) was  to become  the  first 
bishop of the newly founded bishopric in Wolin, which was moved to Kamien 
Pomorski in the second half of the twelfth century. The establishment of the 
bishopric of Lubusz (Lebus), bordering on western Pomerania, in the 1120s 
and  the  establishment  or  perhaps  reestablishment  of  the  bishopric  of 
Wtoctawek, neighbouring Gdansk-Pomerania, were likely to be linked to this 
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