His second wife had died during this year; in 1656 he married a third, who survived him, Margaret, daughter of Lord Spencer, niece of the earl of Southampton, and sister of the earl of Sunderland, who died at Newbury.
He remained at Lincoln, did nothing to prevent the defeat of Essex's army in the west, and when he at last advanced south to join Essex's and Waller's troops his management of the army led to the failure of the attack upon the king at Newbury on the 27th of October 1644.
Sir Robert's grandson, Henry, the 3rd baron, was created earl of Sunderland in June 1643, and was killed at the battle of Newbury when fighting for the king a little later in the same year.
The Cumberland County Court House, of white Maine granite, occupies the block bounded by Federal, Pearl, Church and Newbury streets; immediately opposite (to the south-west) is the Federal Court building, also of Maine granite.
He commanded a troop of horse in Scotland in 1639; was involved in army plots in 1641, for which he was committed to the Tower, but escaped abroad; and on the outbreak of the Civil War returned to England and served with Prince Rupert, being present at Marston Moor, the second battle of Newbury and Naseby.