Mestwin I ( or , ; c. 1160 – 1/2 May 1219 or 1220) was Prince 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 Sobiesà Âaw of Gdaà Âsk and younger brother of Sambor I, whom he succeeded in Pomerelia. In the tables of Oliwa Abbey, outside Gdaà Âsk, 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 à »ukowo), the castellany of Biaà Âogarda at the border with the Pomeranian Lands of Schlawe and Stolp on the à Âeba river, and several villages between the rivers Radunia and Sà Âupia. 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.
He was married to Swinisà Âawa (d. 1240), formerly referred to as a daughter of Duke Ratibor I of Pomerania. They had eight children: