Editing Mieszko I (section)

===War against Bohemia; incorporation of Silesia and Lesser Poland===
{{see also|Polish-Bohemian War (990)}}
Whether or not the German-Polish invasion of Bohemia actually happened, the friendly relations between the Czechs and the Poles came to an end. Bohemia resumed its earlier alliance with the Lutici, which, in 990, resulted in a war with Mieszko, who was supported by Empress [[Theophanu]]. Duke Boleslaus II was probably the first one to attack.<ref>G. Labuda, ''Mieszko I'', p. 171.</ref> As a result of the conflict [[Silesia]] was taken over by Poland. However, the annexation of Silesia possibly took place around 985, because during this year the major [[Piast dynasty|Piast]] strongholds in [[Wrocław]], [[Opole]] and [[Głogów]] were already being built.<ref>Andrzej Buko, "''Archeologia Polski wczesnośredniowiecznej''", 2007, Ed. Trio.</ref>

The issue of the incorporation of [[Lesser Poland]] is also not completely resolved. Possibly Mieszko took the region before 990, which is indicated by the vague remark of Thietmar, who wrote of a country taken by Mieszko from Boleslaus.<ref>''Thietmari chronicon'', vol. I p. 33; argument presented by G. Labuda, ''Mieszko I'', p. 171.</ref> In light of this theory, the conquest of Lesser Poland could be a reason for the war, or its first stage. Many historians<ref>Henryk Łowmiański, ''Początki Polski'', vol. V; A. Buko, ''Małopolska "czeska" i Małopolska "polańska"''</ref> suggested that the Czech rule over Lesser Poland was only nominal and likely limited to the indirect control of [[Kraków]] and perhaps a few other important centers. This theory is based on the lack of archaeological discoveries, which would indicate major building investments undertaken by the Bohemian state.

After its incorporation, Lesser Poland supposedly became the part of the country assigned to Mieszko's oldest son, [[Bolesław I Chrobry|Bolesław]], which is indirectly indicated in the chronicle of Thietmar.<ref>''Thietmari chronicon'', vol. IV chap. 58; this theory is presented by G. Labuda, ''Mieszko I'', p. 176.</ref>

Some historians, on the basis of the chronicle of [[Cosmas of Prague]], believe that the conquest of the lands around the lower Vistula River took place after Mieszko's death, specifically in 999.<ref>In favor: G. Labuda, ''Mieszko I'', pp. 172–173.</ref> There is also a theory according to which during this transition period Lesser Poland was governed by Bolesław, whose authority was granted to him by the Bohemian duke.<ref>Henryk Łowmiański, ''Początki Polski'', vol. V</ref>