Valentine and Thomasine had two sons: —and a daughter: Browne was appointed by Queen Elizabeth in the 1560s to several positions at Berwick-upon-Tweed, an important garrison of the English army on the Scottish border.

He was also involved in financial aspects of the diplomacy and negotiations during the Scottish Reformation and the Marian civil war in which the English supported the King's party led by the Regent Moray who ruled Scotland for the young James VI of Scotland against the Queen's party, which supported Mary, Queen of Scots.

Browne had stayed loyal to Elizabeth and led some troops on this march as we know from a letter he wrote on 16 December 1569 to Henry Carey, 1st Baron Hunsdon, while approaching Durham.

Lesser landlords involved in the rebellion were pardoned upon paying a fine that was collected by Thomas Gargrave, High Sheriff of Yorkshire, who handed the accounts and the money to Browne, treasurer, in July 1570.

After the siege acquired some of the jewels of Mary, Queen of Scots that Sir William Drury brought from Scotland[27] His page Gilbert Edward stole jewels from him including a diamond and ruby studded gold mermaid with a diamond shield or mirror, and a gold chain marked with Sir Valentine's initials "v.

[29][30] When Francis Walsingham travelled to Scotland in August 1583, Sir Valentine wrote to him from Hoxton bemoaning the ruinous state of several castles of the north, including Bamborough, Dunstanburgh, Norham, and Etal.

[32] In a letter to William Cecil, Lord Burleigh, Elizabeth's chief adviser, dated 10 October 1584, Sir Valentine wrote that "the work was so difficult as to have extended over three years.

"[citation needed] He further wrote from Askeaton that he had "travailed hard in superintending the survey, passing through bogs and woods, scaling mountains, and crossing many bridgeless rivers and dangerous waters", waters in which he lost some of his horses, and was twice nearly lost himself; that his son had broken his arm, and that "the service was so severe that many of the men had fallen sick".

He described the towns and villages as ruined, and wrote that "not one of thirty persons" was left alive after the famine caused by crop destructions, and "those for the most part starvelings".

[34] While living at Ross Castle near Killarney, Sir Valentine was in April 1585 elected MP for County Sligo in the Irish parliament of 1585/1586.

[35] In 1586 He was elected MP of Berwick-upon-Tweed for the English Parliament of 1586, which submitted a petition demanding the execution of Mary Stuart, Queen of Scots.

Molahiffe consisted of the territories of Onaght and Coshmaine, which had belonged to two vassals of Donald McCarthy, 1st Earl of Clancare who had sided with the rebels and died in the war.