It became part of the emerging Polish state in the 10th century under its first historic ruler Mieszko I of Poland.
ɪt bɪkˌeɪm pˈɑːɹt ʌvðɪ ɪmˈɜːdʒɪŋ pˈoʊlɪʃ stˈeɪt ɪnðə tˈɛnθ sˈɛntʃɚɹi ˌʌndɚɹ ɪts fˈɜːst hɪstˈɔːɹɪk ɹˈuːlɚ mˈiːszkoʊ aɪ ʌv pˈoʊlənd.