[1] The country was established in 1275, in the partition of the Duchy of Masovia, with duke Konrad II becoming its ruler.

[2] The state was again reestablished in 1310, with Trojden I, as its first ruler.

[3] It existed until 5 November 1370, when, under the rule of duke Siemowit III, duchies of Czersk, Rawa, and Warsaw were unified into the Duchy of Masovia.

[4][5] It was once again reestablished in 1471, from the part of the territories of the duchies of Płock and Warsaw.

[6] It existed until 1495, when, with the incorporation of the Duchy of Płock into the Kingdom of Poland, it remained the only state in Masovia, and subsequently, got reformed into the Duchy of Masovia.