One of the most important victories of the magnates was the late 16th century right to create ordynacja's (similar to majorats), which ensured that a family which gained wealth and power could more easily preserve this. Ordynacje's of families of Radziwiłł, Zamoyski, Potocki or Lubomirski <answer>often rivalled</answer> the estates of the king and were important power bases for the magnates.
What did the powerful families do with the kings estates?
often rivalled