The voivodeship was officially created by King Sigismund I the Old on December 27, 1529, three years after the incorporation of the Duchy of Masovia into the kingdom.

This vast land was part of the Kingdom of Poland from the 10th until the 12th century (...) Divided into several smaller parts, it nevertheless remained a separate entity, ruled by one dynasty, with one political, social and legal system.

In the years 1462, 1495 and 1526, Mazovian lands were gradually incorporated back into Poland, and divided into three voivodeships – Rawa Mazowiecka, Płock and Mazovia.

miles, and all three Mazovian voivodeships were divided into 33 counties, with 446 Roman-Catholic parishes, 94 towns and 5990 villages.

Still, Mazovia was among the most densely populated provinces of Poland, together with Łęczyca Land, Kujawy and Dobrzyń Land.Seat of the Voivodeship Governor (Wojewoda):