Mestwin I, Duke of Pomerania

Mestwin I (Polish: Mściwój I gdański or Mszczuj I, Kashubian: Mscëwòj I; born c. 1160, died 1/2 May 1219 or 1220) was regent (a "namiestnik" or starosta) of Pomerelia (styled himself as princeps Pomoranorum) from about 1205 until his death.

Mestwin was a member of the Samborides dynasty, the son of Duke Sobiesław of Gdańsk and younger brother of Sambor I, whom he succeeded in Pomerelia by appointment of the Polish High Duke Władysław III Spindleshanks. In the tables of Oliwa Abbey, he is recorded as pacificus ("the Peaceful").

As Mestwin I, dei gracia princeps in Gdanzk, he had founded a convent of nuns (probably the Premonstratensian abbey of Żukowo), the castellany of Białogarda at the border with the Pomeranian Lands of Schlawe and Stolp on the Łeba river, and several villages between the rivers Radunia and Słupia. After King Valdemar II of Denmark had conquered the southern coast of the Baltic Sea with Gdanzk during a crusade against the Old Prussians, Duke Mestwin in 1210 had to accept Danish overlordship, but was able to free himself again the next year.

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