Boleslaw II, due to his involvement in…
1066 CE
Boleslaw II, due to his involvement in Hungarian, Bohemian and Kievan affairs, has neglected Poland's interests on the Baltic coast.
Western Pomerania, therefore, had been lost first; then, in either 1060 or 1066, eastern Gdańsk Pomerania (Pomerelia) also severs its ties to the Polish Kingdom.