Although the O'Neill had allied himself against the English with the Scottish MacDonnell clan, who had settled in Antrim, Queen
Elizabeth I, on succeeding to the English throne in 1558, was inclined to come to terms with the O'Neill, who after his father's death functioned as
de facto head of the dynasty. She accordingly agreed to recognise his claims to the lordship, throwing over Brian O'Neill, son of the assassinated Feardorcha, Baron of
Dungannon, if the O'Neill would submit to her authority and that of her deputy. O'Neill refused to put himself in the power of the Earl of Sussex,
Thomas Radclyffe, without a guarantee for his safety; and so Elizabeth decided to establish Brian in his place. An attempt by Sussex to increase the enmity of the O'Donnells against the O'Neill was frustrated by his seizure of
Calvagh O'Donnell in a monastery. Elizabeth, whose prudence and parsimony were averse to so formidable an undertaking as the complete subjugation of the powerful O'Neill, desired peace with him at almost any price. Elizabeth's faith in Sussex's aggressive strategy diminished when the repeated annual devastations of O'Neill's territory by the Lord Deputy with sizeable and expensive armies failed to bring him to submission. The O'Neill destroyed the greater part of Sussex's invasion army at the
Battle of the Red Sagums, 18 July 1561, while Sussex was deep in O'Neill-controlled territory garrisoning Armagh with a small body of men. Afterwards, Elizabeth sent the Earl of Kildare to arrange terms with the O'Neill, who was demanding a complete withdrawal of the English from his territory. Unable to succeed against O'Neill in battle, Sussex tried in 1561 to assassinate him using poisoned wine. The O'Neill now called the lord deputy to account for his unnatural enmity, as displayed in this most recent of many attempts on his life. Elizabeth consented to treat, and hostilities ceased on terms that gave the O'Neill practically all his demands. The O'Neill offered some concessions, most significantly consenting to present himself before Elizabeth in London to argue his case against Sussex and the Baron of Dungannon in person. The O'Neill requested the hand of Sussex's half-sister
Lady Frances Radclyffe in marriage as an earnest of future friendship. Accompanied by the Earls of Ormonde and Kildare as surety for his safety, the O'Neill reached London on 4 January 1562.
William Camden describes the wonder which his
gallowglasses occasioned in the English capital, with their heads bare, their long hair falling over their shoulders and clipped short in front above the eyes, and clothed in saffron-dyed shirts of fine linen. Elizabeth was less concerned with the respective claims of Shane O'Neill and the Baron of Dungannon, the former resting on Gaelic law, the latter on an English patent, than with the question of policy involved. Characteristically, she temporised; but fearing that Shane could become a tool of Spanish intriguers, she permitted him to return to Ireland, recognising him as The O'Neill. (Elizabeth's recognition of his claim to the title the O'Neill was meaningless, except symbolically, as she had no authority to confirm a title conferred under
Brehon law.) During this visit, Shane's legal claim to his father Conn Bacach's earldom was verbally confirmed and Shane was led to believe that he would be recognised as the 2nd Earl of Tyrone, though some reservation was made of the possible future rights of
Hugh O'Neill, who had succeeded his brother Brian as Baron of Dungannon. Brian had been killed in a skirmish in April 1562 by Shane's
tanist,
Turlough Lynagh O'Neill. However, confirmation of the grant of the earldom was never delivered, and the O'Neill was compelled to defend his hegemony in Ulster when his onetime supporter Sir
Henry Sidney was appointed Lord Deputy and resurrected Sussex's policy of undermining the O'Neill's authority. ==War in Ulster==