On 9 February 1527, Parr married Anne Bourchier, 7th Baroness Bourchier, daughter of Henry Bourchier, 2nd Earl of Essex.
On 17 April 1543, their marriage was annulled by an Act of Parliament and her children (by her lover) were declared bastards.
Parr also obtained his ex-wife's lands and titles, being created Earl of Essex on 23 December 1543.

He later married Elisabeth Brooke, daughter of George Brooke, 9th Baron Cobham.
Their marriage was declared valid in 1548, invalid in 1553, and valid again in 1558.
Elisabeth died in 1565; five months before he died, he married Helena Snakenborg, a lady in waiting from Sweden.
According to the International Genealogical Index (IGI), Parr may have bore a son with Elizabeth in Prescot named Richard in 1542.
On 9 February 1527, Parr married Anne Bourchier, 7th Baroness Bourchier, daughter of Henry Bourchier, 2nd Earl of Essex. On 17 April 1543, their marriage was annulled by an Act of Parliament and her children (by her lover) were declared bastards. Parr also obtained his ex-wife's lands and titles, being created Earl of Essex on 23 December 1543.
He later married Elisabeth Brooke, daughter of George Brooke, 9th Baron Cobham. Their marriage was declared valid in 1548, invalid in 1553, and valid again in 1558. Elisabeth died in 1565; five months before he died, he married Helena Snakenborg, a lady in waiting from Sweden. According to the International Genealogical Index (IGI), Parr may have bore a son with Elizabeth in Prescot named Richard in 1542.
William Parr, 1st Marquess of Northampton