Context: Significant legislative changes in the status of the szlachta, as defined by Robert Bideleux and Ian Jeffries, consist of its 1374 exemption from the land tax, a 1425 guarantee against the 'arbitrary arrests and/or seizure of property' of its members, a 1454 requirement that military forces and new taxes be approved by provincial Sejms, and statutes issued between 1496 and 1611 that prescribed the rights of commoners.

Question: Who defined the significant legislative changes?
Answer: Robert Bideleux and Ian Jeffries

Question: What is one exemption was part of the significant changes in legislation?
Answer: 1374 exemption from the land tax,

Question: What did the 1425 requirement entail? 
Answer: requirement that military forces and new taxes be approved by provincial Sejms

Question: What were the statutes issued between 1496 and 1611 prescribed from?
Answer: rights of commoners