[1] It existed in the High Middle Ages era, from 1275 to 1294, from 1310 to 1351, and from 1381 to 1462.

The country was established in 1275, in the partition of the Duchy of Masovia, with duke Bolesław II of Masovia becoming its ruler.

[2] The state was again reestablished in 1310, in the partition of Duchy of Masovia.

[3][4] It was again reestablished in June 1381, in the partition of the Duchy of Masovia, with duke Siemowit IV as its first leader.

[5][6][7] It existed until 1462, when it got partitioned between the Kingdom of Poland, and the Duchy of Warsaw.