Duke of Masovia ( pl, Książę Mazowsza) was a title born by the sons and descendants of the Polish Duke

Bolesław III Wrymouth Bolesław III Wrymouth ( pl, Bolesław III Krzywousty; 20 August 1086 – 28 October 1138), also known as Boleslaus the Wry-mouthed, was the duke of Lesser Poland, Silesia and Sandomierz between 1102 and 1107 and over the whole of Poland between ...

. In accordance with the

last will and testament A will or testament is a legal document that expresses a person's (testator) wishes as to how their property ( estate) is to be distributed after their death and as to which person (executor) is to manage the property until its final distributio ...

of Bolesław, upon his death his lands were divided into four to five hereditary provinces distributed among his sons, and a royal province of

Kraków Kraków (), or Cracow, is the second-largest and one of the oldest cities in Poland. Situated on the Vistula, Vistula River in Lesser Poland Voivodeship, the city dates back to the seventh century. Kraków was the official capital of Poland un ...

reserved for the eldest, who was to be High Duke of all Poland. This was known as the

fragmentation of Poland The period of rule by the Piast dynasty between the 10th and 14th centuries is the first major stage of the history of the Polish state. The dynasty was founded by a series of dukes listed by the chronicler Gall Anonymous in the early 12th cen ...

. Subsequent developments lead to further splintering of the duchies. The following is a list of all rulers of the

Duchy of Masovia Duchy of Masovia was a district principality and a fiefdom of the Kingdom of Poland, existing during the Middle Ages. The state was centered in Mazovia in the northeastern Kingdom of Poland, and during its existence, its capital was located i ...

and its parts. Although not all incumbents listed here had titular rights to the title of Duke of Masovia, they are all listed as such for simplicity's sake. Also take note that some of the dates are merely approximate and the ownership of certain lands might be disputed. Finally, this table does not include lands ruled by dukes of other parts of partitioned

Poland Poland, officially the Republic of Poland, is a country in Central Europe. It is divided into 16 administrative provinces called voivodeships, covering an area of . Poland has a population of over 38 million and is the fifth-most populou ...

or Wenceslaus II and Wenceslaus III.

Duchy of Masovia

Partitions of Masovia

The Duchy went through various border changes in the coming years, sometimes losing and sometimes gaining territory.

Dukes of Masovia

Piast Dynasty The House of Piast was the first historical ruling dynasty of Poland. The first documented Polish monarch was Duke Mieszko I (c. 930–992). The Piasts' royal rule in Poland ended in 1370 with the death of king Casimir III the Great. Branch ...

Duchy of Masovia

Partitions of Masovia

Dukes of Masovia

Piast Dynasty The House of Piast was the first historical ruling dynasty of Poland. The first documented Polish monarch was Duke Mieszko I (c. 930–992). The Piasts' royal rule in Poland ended in 1370 with the death of king Casimir III the Great. Branch ...

See also