William Parr, 1st Marquess of Northampton and 1st Earl of Essex KG (c. 1512 – October 28 1571) was the son of Sir Thomas Parr and his wife, Maud Green, daughter of Sir Thomas Green, of Broughton and Green's Norton, and brother of Katherine Parr, the sixth and final wife of Henry VIII.
On February 9 1526, William married Anne Bourchier, 7th Baroness Bourchier, daughter of Henry Bourchier, 2nd Earl of Essex. On April 17 1543, their marriage was annulled by an Act of Parliament and her children were declared bastards.
Their marriage was declared valid in 1548, invalid in 1553, and valid again in 1558.
He was Edward VI's 'beloved uncle' and one of the most important men at Edward's court, especially during the time of John Dudley, 1st Duke of Northumberland's time as leader of the government. Parr, and especially his wife, were leaders in the plot to put Lady Jane Grey on the throne after Edward's death.
Five months before he died, he married Helena Snakenborg, a lady in waiting, who was from Sweden.
He was created Baron Parr of Kendal in 1539, Earl of Essex in 1543 and Marquess of Northampton in 1547. He was stripped of these titles by Mary I in 1553, but they were restored by Elizabeth I in 1559. On his death, as he had no children, the titles became extinct.
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