William was the first of Essex's commanders to be ambushed by Irish forces and when his horse was killed under him, near Massereene, east of Lough Neagh, John saved his brother from being slain.
When Lord Essex entered County Antrim, it was to Rathlin Island that the Scots Highlanders of Clan MacDonald of Dunnyveg led by Somhairle Buidhe MacDonnell sent their wives and children, their aged and sick, for safety.
In 1577, Norreys led a force of English volunteers to the Low Countries, where he fought for the States General, then in revolt against the rule of the Spanish King Philip II at the beginning of the Eighty Years' War.
In March 1584, Norreys departed the Low Countries and was sent to Ireland in the following July, where he was appointed Lord President of Munster (at this time, his brother Edward was stationed there).
Norris urged the Plantation of Munster with English Puritans (an aim adopted in the following years), but the situation proved so unbearably miserable that many of his soldiers deserted him for the Low Countries.
The purpose, once again, was to dislodge the Highlander Scots of Clan MacDonald of Dunnyveg, who, led by Somhairle Buidhe MacDonnell, had migrated into both the Route and the Glens of Antrim.
The campaign was unsuccessful, as what is now called the Clan MacDonald of Antrim simply regrouped in Kintyre before crossing back to Ireland after the lord deputy had withdrawn south.
In April 1585, the jailer at Clonmel, County Tipperary was bribed by Victor White, a leading townsman, to release imprisoned Roman Catholic priest Fr.
Mac Ionrachtaigh, however, resolutely maintained the Roman Catholic faith and the Petrine Primacy and was accordingly condemned by Sir John Norreys, "after much invective", to death for high treason.
Mac Ionrachtaigh a full pardon in return for taking the Oath of Supremacy and naming those local Catholics who had attended his Mass or secretly received the Sacraments from him.
According to Bishop David Rothe, "When he came to the place of execution, he turned to the people and addressed them some pious words as far as time allowed; in the end he asked all Catholics to pray for him and he gave them his blessing.
Upon news of the siege of Antwerp, Norreys urged support for the Dutch Protestants and, transferring the presidency of Munster to his brother, Thomas, he rushed to London in May 1585 to prepare for a campaign in the Low Countries.
Still, his army of untried English foot did repulse the Duke of Parma in a day-long fight at Aarschot[citation needed] and remained a threat, until supplies of clothing, food and money ran out.
His men suffered an alarming mortality rate without support from home, but the aura of invincibility attaching to the Spanish troops had been dispelled, and Elizabeth finally made a full commitment of her forces to the States General.
During an attack on Parma, Norreys received a pike wound in the breast, then managed to break through to relieve Grave,[citation needed] the last barrier to the Spanish advance into the north; Leicester knighted him for this victory during a great feast at Utrecht on St George's Day, along with his brothers Edward and Henry.
He oversaw a troop withdrawal in preparation for an expedition to Portugal designed to drive home the English advantage following the defeat of the Spanish Armada, when the enemy's fleet was at its weakest.
Some of his troops transferred to the Earl of Essex's force in Normandy, and Norreys' campaign proved so indecisive that he left for England in February 1592 and did not return to the Duchy of Brittany until September 1594.
Afterwards, he was part of the force that besieged and brutally assaulted and captured Fort Crozon outside Brest, defended by 400 Spanish troops, as well as foiling the relief army under Águila.
Sir Robert Devereux, 2nd Earl of Essex had wanted his men placed as Russell's subordinates, but Norreys rejected this and was issued with a special patent that made him independent of the lord deputy's authority in Ulster.
After flourishing his letters patent at Drogheda upon the proclamation of Aodh Mór Ó Néill, Chief of the Name of Clan O'Neill and Lord of Tír Eoghain, as guilty of high treason, Norreys made his headquarters at Newry and fortified Armagh cathedral.
Norreys camped his troops along the River Blackwater, while Clan O'Neill roamed the far bank; a ford was secured but no crossing was attempted because there was no harvest to destroy and a raid within enemy territory would have been futile.
So long as Russell was with the army, Norreys refused to assume full responsibility, which prompted the lord deputy to return to Dublin in July 1595, leaving his commander a free hand in the conquest of Ulster.
He informed the queen's secretary, Sir William Cecil, that the Ulster Clans were far superior in strength, arms and munitions to any he had previously encountered, and that the English needed commensurate reinforcement.
He censured the presidential government of Sir Richard Bingham for having stirred up the lords into rebellion - although the influence of Tyrone's ally, Hugh Roe O'Donnell, in this respect was also recognised, especially since Sligo castle had lately fallen to the rebels.
However, during a campaign of six months, Norreys failed to restore peace to Connaught, and despite a nominal submission by the lords, hostilities broke out again as soon as he had returned north to Newry in December 1596.
Being unclear as to how Dublin wanted to deal with him, Norreys remained at Newry negotiating with Tyrone, while Russell was replaced as lord deputy by Thomas Burgh, 7th Baron Strabolgi.
At his brother's house in Mallow, he developed gangrene, owing to poor treatment of old wounds, and was also suffering from a settled melancholia over the disregard by the crown of his 26 years’ service.
Another version, recounted by Philip O'Sullivan Beare, states that a servant boy, on seeing Norreys go into the chamber in the company of a shadowy figure, had listened at the door and heard the soldier enter a pact with the Devil.
In 1600, during the course of the Nine Years' War, Sir Charles Blount, Lord Mountjoy, the commander who eventually defeated Tyrone, built a double-ditch fort between Newry and Armagh, which he named Mountnorris in honour of Norreys.
Mountjoy referred to Norreys as his tutor in war, and took note of his former understanding that Gaelic Ireland was not to be brought under the control of the Crown except by force and large permanent garrisons.