The Earl acknowledged his son and made financial arrangements on his behalf with an addendum to his will in July 1595, "Walter Devereux the base and reputed sonne of the said Robt Erle of Essex, begotten of the body of Eliz: Southwell.
[4] The lack of adequate means was probably the principal cause that Devereux spent most of his adult life in Essex's household in Staffordshire and Westminster, and although he persistently described himself as being ‘of Lamphey’ there is no evidence to suppose that he ever lived there.
Walter was given over to the care of Essex's mother, Lettice (Knollys) (Devereux) Dudley, Countess of Leicester, who raised him at Drayton Bassett in Staffordshire.
Walter signed with Richard Oubeley the following "Declaration of Essex’s Seconds":[5] Whereas there has been a new relation of the quarrel betwixt my Lord of Essex and Mr. Henry Howard, after his Majesty had reconciled them, made by the four seconds before Sir Horatio Vere and Sir John Wentworth, and the same being drawn into the brief by Mr. Horton, one that was secretary to the last Lord Treasurer, and we setting our hands thereto, not reading it, but only hearing it read, not mistrusting anything, but to find just dealing, have since seen a copy thereof, which we find contrary to that which was then agreed upon, and merely false in some main points; we have a sight of the original copy for our satisfaction, not to satisfy the world, for the which we do unjustly suffer a hard censure.
The final insult happened a few weeks later when the Howard family demanded his wife's dowry back, and Essex was forced to sell parts of his estate and borrow money from his grandmother, Lettice the Countess of Leicester.
The two brothers were now joined more closely, and as a retainer of the 3rd Earl of Essex, Walter found himself strongly in opposition to the Stuart monarchy, and a staunch supporter of Parliament in the evolving Civil War.
[6] On 2 February 1618 he performed in "The Fairies’ Farewell: The Masque at Coleorton" at his half-sister, Frances Devereux's marriage to Sir William Seymour.
Essex returned to England in December 1620 to try to obtain additional troops that were promised him, but failed leading to his volunteering for service under Prince Maurice, at the "leaguer of Dernick.
His family ties were further strained when in mid-1636 his half-brother, Robert Earl of Essex, became suspicious his second wife, Elizabeth Paulet, was having an affair.
It was probably this Devereux who was named to the committee for the bill to authorize the sale of the Staffordshire lands of the two Thomas Copes, father and son (16 March 1624).
[4] It also seems likely that it was he who attended one of the four committee meetings concerned with the bill to reverse a decree in the Court of Requests involving two Welshmen, as he was appointed by virtue of being a Member for a Welsh constituency.
[1] In February 1628 he was appointed to help draft a bill to regulate the lieutenancy (24 March 1628) and to consider a measure aimed at preventing bribery and the purchase of judicial office (23 January 1629).
As the Second Bishops War ended in disaster, Charles I summoned parliament again on 24 September and Walter Devereux was a member for Lichfield once more.
[1] The ‘Long Parliament’ began on 3 November 1640 and Walter Devereux served on the Ship Money Committee and was named one of the Commissioners for Staffordshire in the Scandalous Ministers Act.
[9] Walter Devereux's grandmother, Lettice Dudley Countess of Leicester, wrote to Robert Cecil, 1st Earl of Salisbury, in 1608 to assist in arranging his marriage to "Lady Stallenge’s daughter".
The daughter most likely referred to in the letter was Margaret who ended up marrying Sir William Guise in 1608, and died before 1612 after bearing him a single son and heir.