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.
- Mirosława, married Bogislaw II, Duke of Pomerania at Stettin
- Swietopelk II, Duke of Pomerania, succeeded his father as Duke of Pomerelia, from 1227 of Pomerelia-Gdańsk
- (doubtful) Jadwiga, married Duke Władysław Odonic of Greater Poland
- Witosława, prioress of Żukowo Abbey
- Warcisław, Duke at Świecie from 1227
- Sambor II, Duke at Lubiszewo from 1233
- Ratibor, Duke at Białogard from 1233
- Milosława, nun at Żukowo Abbey
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- On a recently-discovered Seal-stamp of Duke Mestwin I., of East Pomerania," by H. Ernst Strehlke. - The Numismatic Chronicle, p. 158, Royal Numismatic Society (Great Britain), 1966 
- Gumowski, Marian (1867). Handbuch der polnischen Siegelkunde (in German). Akademische Druck- u. Verlagsanstalt. pp. 51, 67, 69.
- Loew PO: Danzig. Biographie einer Stadt, Munich 2011, p. 32: "Sambor [...] styled himself 'princeps Pomoranorum,' [...], but not 'dux,' which was the privilege of the Piasts." p. 33: "After Sambor's death [...] his brother Mestwin [...] strove after gaining ever greater independence from Poland. He confidently styled himself 'princeps in Danzk' and expanded southwards. His oldest son Swantopolk (Swietopelk), ruling from 1217 onwards, exploited Poland's fragmentation to acquire independence for his realm; already since 1227 he styled himself 'dux,' 'Duke of Pomerelia.'"
- Wspomniany Mestwin I ... znamiennym zwrotem nunc princeps in Gdanzk podkreślił, że obecnie już nie w jednym z podrzędnych, ale w naczelnym grodzie się ..., p.59 of Zapiski historyczne, by Towarzystwo Naukowe w Toruniu, Wydział Nauk Historycznych 
- Urban, William (2000). The Prussian Crusade (2nd ed.). Chicago, Illinois: Lithuanian Research and Studies Center. p. 185. ISBN 0-929700-28-7.
- Brown Mason, John (1946). The Danzig Dilemma: a Study in Peacemaking by Compromise. Oxford University Press.
- Hirsch, Theodor; Max Töppen; Ernst Strehlke (1861). Scriptores rerum Prussicarum: Die Geschichtsquellen der preussischen Vorzeit (in German). S. Hirzel.
- Theodor Hirsch, Max Töppen, Ernst Gottfried Wilhelm Strehlke: Scriptores Rerum Prussicarum: Die Geschichtsquellen der preussischen Vorzeit
- Max Perlbach (1885), "Mestwin I., Herzog von Pomerellen", Allgemeine Deutsche Biographie (ADB) (in German), 21, Leipzig: Duncker & Humblot, pp. 503–504
Mestwin I, Duke of PomeraniaBorn: ~ 1160 Died: 1219/20
| Duke of Pomerelia