According to Polish legend, Mieszko I inherited the ducal throne from his father who probably ruled over two-thirds of the territory inhabited by eastern Lechite tribes. He united the Lechites east of the Oder (Polans, Masovians, Pomeranians, Vistulans, Silesians) into a single country of Poland. His son, Bolesław I the Brave, founded the bishoprics at Wrocław, Kołobrzeg, and Kraków, and an archbishopric at Gniezno. Bolesław carried out successful wars against Bohemia, Moravia, Kievan Rus' and Lusatia, and forced the western Pomeranians to pay Poland a tribute. Shortly before his death Bolesław became the first King of Poland in 1025.
The West Slavs included the ancestors of the peoples known later as Poles, Pomeranians, Czechs, Slovaks, Sorbs and Polabians. The northern so-called Lechitic group includes, along with Polish, endangered Pomeranian and Polabian, a dead language; Silesian, which is variously considered a Polish dialect or a language in its own right, is also part of this group. The Sorbian languages of the southern part of the Polabian area, preserved as relics today in Upper and Lower Lusatia, occupy a place between the Lechitic and Czech-Slovak groups.[5]
In Polish literature Lech was also the name of the legendary founder of Poland. The legend describes three brothers, Lech, Čech, and Rus – who founded three Slavic nations: Poland (also known as Lechia), Bohemia (Čechy, now known as the Czech Republic), and Rus (Ruthenia). In this legend Lech was the founder of Gniezno.
Three brothers Lech, Czech and Rus were exploring the wilderness to find a place to settle. Suddenly they saw a hill with an old oak and an eagle on top. Lech said: this white eagle I will adopt as an emblem of my people, and around this oak I will build my stronghold, and because of the eagle nest (Polish: gniazdo) I will call it Gniezdno (modern: Gniezno). The other brothers went further on to find a place for their people. Czech went to the South (to found the Czech Lands) and Rus went to the East (to create Rus').[12]
A variant of this legend, involving only two brothers Lech and Čech, was first written down by Cosmas of Prague of Bohemia. The legend was described by Kronika wielkopolska ("Greater Poland Chronicle"),[14] written in 1273 in Latin, and Chronicle of Dalimil, written in Czech in 1314.[15]
^"Laesir is the Old Norse term for the Ljachar, a people near the Vistula in Poland". [in:] Theodore Murdock Andersson, Kari Ellen Gade Morkinskinna: The Earliest Icelandic Chronicle of the Norwegian Kings (1030–1157). ISBN978-0-8014-3694-9 p. 471; "The word here for Poles is "Laesum" – the dative plural from a nominative plural "Laesir". This clearly is derived from the old name for Pole – "Lyakh", since in the course of the Slavonic paradigm -kh- becomes -s-in accordance with the "second palatalization" and the addition of the regular Norse plural ending of -ir- [...] [in:] The Ukrainian review. 1963. p. 70; "eastern Wends, meaning obviously the Vjatyci/Radimici, Laesir "Poles" or "Western Slavs" (ef. Old Rus'ian ljaxy) [in:] Omeljan Pritsak. Old Scandinavian sources other than the sagas. 1981. p. 300
^ abHenryk Paszkiewicz. The making of the Russian nation. Greenwood Press. 1977. p. 353.
^Bohemia and Poland. Chapter 20.pp 512-513. [in:] Timothy Reuter. The New Cambridge Medieval History: c. 900-c.1024. 2000
^Knoll & Schaer (eds.), Gesta Principum Polonorum: The Deeds of the Princes of the Poles, (Budapest, 2003
^Ljudmila Mikhailovna Popova (ed.), Gall Anonim, Khronika u Deianiia Kniazei ili Pravitelei Polskikh, (Moscow, 1961
^Laurence Mizler de Kolof (ed.), Historiarum Poloniae et Magni Ducatus Lithuaniae Scriptorum Quotquot Ab Initio Reipublicae Polonae Ad Nostra Usque Temporar Extant Omnium Collectio Magna, (Warsaw, 1769
^Wood, Raymond F. (tr.). "The three books of the deeds of the Saxons, by Widukind of Corvey, translated with introduction, notes, and bibliography." Dissertation. University of California, Los Angeles, 1949. English translation
^"Monumenta Poloniae historica" T. 2 red. August Bielowski, Lwów 1872
^ ab"Kronika wielkopolska" ("Greater Poland Chronicle"), Kazimierz Abgarowicz, Brygida Kürbisówna, PWN, Warszawa 1965, second edition Kraków 2010, ISBN978-83-242-1275-0
^Theodore Murdock Andersson, Kari Ellen Gade Morkinskinna: The Earliest Icelandic Chronicle of the Norwegian Kings (1030–1157). ISBN978-0-8014-3694-9 p. 471
^Brygida Kürbisówna, "Studia nad Kroniką wielkopolską", Poznańskie Towarzystwo Przyjaciół Nauk, Poznań 1952
^Die alttschechische Reimchronik des sogenannten Dalimil, Munich: Sagner, 1981