Context: Magnates often received gifts from monarchs, which significantly increased their wealth. Often, those gifts were only temporary leases, which the magnates never returned (in the 16th century, the anti-magnate opposition among szlachta was known as the ruch egzekucji praw—movement for execution of the laws—which demanded that all such possessions are returned to their proper owner, the king).

Question: Magnates recieved gifts often from who?
Answer: monarchs

Question: What significantly increased the magnates wealth?
Answer: Magnates

Question: What terms were these gifts given?
Answer: temporary leases

Question: What did the magnates do eventually with the gifts?
Answer: never returned