The powerful Ó Néill clan of Tyrone dominates the center of the northern province of Ulster; Conn Ó Neill the Lame had been the first Ó Neill be created Earl of Tyrone under English law.

Hugh Ó Neill, the son of Mathew of Dungannon, who was the son of Conn Ó Neill the Lame, had seen his father killed and had himself been banished from Ulster as a child by Seán 'An Díomais' Ó Néill.

Brought up by the Hovenden family in the Pale, he had been sponsored by the English authorities as a reliable lord.

He had in 1587 persuaded Queen Elizabeth to make him Earl of Tyrone (or Tir Eoghain), the English title his grandfather had held.

The real power in Ulster, however, lies not in the legal title of Earl of Tyrone, but in the position of The Ó Néill, or chief of the Ó Neill clan, held at this time by Turlough Luineach Ó Neill.

It is this position that commands the obedience of all the Ó Neills and their dependents in central Ulster.

His constant disputes with Turlough have been fomented by the English with a view to weakening the power of the O'Neills, but with the growing power of Hugh, the two come to some agreement in 1595 and Turlough abdicates.

Hugh is subsequently inaugurated as The O'Neill at Tullahogue in the style of the former Gaelic kings, and becomes the most powerful lord in Ulster.

The ambitions of this Gaelic Irish chieftain are at odds with those of the advance of the English state in Ireland, from control over the Pale to ruling the whole island.

In resisting this advance, Ó Neill has managed to rally other Irish septs who are dissatisfied with English government and some Catholics who oppose the spread of Protestantism in Ireland.

From Hugh Roe Ó Donnell, his ally, he has enlisted Scottish mercenaries (known as Redshanks).

Within his own territories, O'Neill is entitled to limited military service from his sub lords or uirithe.

He has also pressed his tenants and dependents into military service and tied the peasantry to the land in order to increase food production.

In addition, he has hired large contingents of Irish mercenaries known as buanadha under leaders such as Richard Tyrell.

To arm his soldiers, Ó Neill has bought muskets, ammunition and pikes from Scotland and England.

Ó Donnell, on Ó Neill’s behalf, has from 1591 been in contact with Philip II of Spain, appealing for military aid against their common enemy and citing also their shared Catholicism.

With the aid of Spain, Ó Neill has been able to arm and feed over eight thousand men, unprecedented for a Gaelic lord, and so is well prepared to resist any further English attempts to govern Ulster.

Norreys, having fallen foul of his French colleagues at the end of 1594, had returned from Brest.

He is in April 1595 selected as the military commander under the new lord deputy of Ireland, Sir William Russell.

The waspish Russell had been governor of Flushing, but the two men are on bad terms.

Sir Robert Devereux, 2nd Earl of Essex, had wanted his men placed as Russell's subordinates, but Norreys rejects this and is issued with a special patent that makes him independent of the lord deputy's authority in Ulster.

It is expected that the terror of the reputation he has gained in combating the Spanish will be sufficient to cause the rebellion to collapse.

English government in Ulster in the early 1590s has taken the form of a Provincial Presidency, headed by the colonist Sir Henry Bagenal who lives at Newry.

O'Neill had roused the ire of Bagenal in 1591 by eloping with his sister, Mabel, but in 1593 had showed his loyalty to the crown with his military support for his brother-in-law in the defeat of Hugh Maguire at Belleek.

After Mabel's death, O'Neill had gradually fallen into a barely concealed opposition to the crown and sought aid from Spain and Scotland.

The Nine Years War begins with a conflict over English efforts to maintain a string of garrisons along the southern border of Tyrone's territory in Ulster.

The Irish leader promptly besieges the English garrison at Monaghan castle, and Bagenal marches out to its relief on May 25 (June 4 New Style) from Dundalk, via Newry.

His army is made up of seventeen hundred and fifty troops, including some veterans and certain companies newly arrived from the Spanish campaign in Brittany, but there are many recruits in the ranks.

Bagenal's men are predominantly infantry, armed with muskets and pikes; there is also a small number of horsemen raised in the Pale.

The Battle of Clontibret is essentially a two day running fight, as Bagenal's column is ambushed on its way to and from Monaghan town.

It ends in victory for Tyrone, and is the first severe setback suffered by the English during the war.

Sir John Norreys, owing to troubles in the province of Connaught, arrives with Sir Geoffrey Fenton in June 1596 to parley with the local lords.

He censures 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 is also recognized, especially since Sligo castle had lately fallen to the rebels.

Bingham is suspended and detained in Dublin (he will later be detained in the Fleet in London).

During a campaign of six months, Norreys fails however to restore peace to Connaught, and, despite a nominal submission by the lords, hostilities beak out again in December 1596 as soon as he has returned north to Newry.

Heartily sick of his situation at this point, Norreys seeks to be recalled, citing poor health and the effect upon him of various controversies.

Russell, as usual, weighs in with criticism and claims that Norreys is feigning poor health in Athlone and seeking to have the lord deputy caught up in his failure.

An analysis of this situation in October 1596, which had been backed by the Earl of Essex, had it that Norreys' style was "to invite to dance and be merry upon false hopes of a hollow peace".

This approach is in such contrast to Russell's instincts that there is a risk of collapse in the Irish government.

It is decided in the end to remove both men from Ulster in late 1596, sending Russell back to England and Norreys to Munster.

Essex had waited at Helbry, an island at the mouth of the river Dee, for favorable winds in foggy conditions on April 5; a week later he had sailed from Beaumaris after impatiently riding over Penmaen Mawr while bidding his ships to follow him—"the worst way and in the extremest wet that I have endured".

After a violent passage, he reaches Dublin on April 15 and is sworn in to office the same day, when the Archbishop of Dublin preaches a notable sermon.

Within a week of his arrival, Essex mounts a lavish pageant of English chivalry during the Garter feast at Dublin on St. George's Day, April 23.

It is intended as a pointed display of the values he feels are ignored in Elizabeth's court.

The Queen had chosen a muted version of the same ceremony at home, owing to the hardships of the war, and on hearing the reports from Dublin she decides to grant the masterships of wards—a significant source of wealth—to Cecil rather than Essex.

Essex is followed from England by the Earl of Kildare, with eighteen of the chiefs of Meath and Fingal, but their vessel founders in mid-channel, and all on board are lost.

Another English general, Arthur Chichester, lands at Dublin and marches his men to Drogheda, where Essex follows to inspect the famous twelve hundred strong Flanders regiment on parade: Essex charges them with his mounted staff, but the soldiers choose not to see the joke and stand firm, forcing Essex to pull his horse back just as his backside is pricked with a pike.

The grand strategy favored at Dublin, of attacking by land and sea simultaneously, is probably impossible with English resources, given the rumors of a fresh Armada from Spain and the consequent need to keep the warships in southern waters.

Contrary to the urgings of the Irish council, the privy council at London settles on a straight land campaign against the northern rebels, and the plan for an amphibious expedition to establish a base at Lough Foyle in O'Neill's rear in the northern province of Ulster is abandoned.

The Dublin council now advises Essex to refrain from an immediate attack on O'Neill and his fellow rebel, Hugh Roe O'Donnell.

Experience suggests that the want of forage, with lean cattle and weak draft-horses, would crucially hinder a northern campaign at this point.

Instead, it is suggested that he attack the rebel allies in the province of Leinster adjacent to Dublin, where, of the total number of rebels in arms, three thousand are reckoned to have risen out alongside eight hundred mercenaries from Ulster.

In the north O'Neill displays his strategic strength by stripping the lands bordering the Pale of all food and horses, in an attempt to forestall an expedition into Ulster.

In the south O'Neill encourages a rebellion by Edmund FitzGibbon—who had inherited the Anglo-Norman title of the White Knight and has struggled to maintain his loyalty to the crown—and others in Munster, in order to distract Essex.

In the west O'Donnell moves into Connacht, and it is believed that O'Neill will follow him and join with the White Knight.

The borders of the Pale are garrisoned with five thousand of Essex's troops, garrisons around Cork are reinforced, and more troops are absorbed in Munster by Sir Thomas Norris (acting president of this province) and at Kilkenny by the Earl of Ormond.

Sir Conyers Clifford's Connacht army is also increased to three thousand.

Operating on intelligence that O'Neill is set to move into Munster, while O'Donnell is already in north Connacht, Essex sets out from Dublin on May 9 to muster his army in ...

...the champion fields of Kildare, the curraghs.

He marches south, ...

...taking the castle of Athy, and ...

...is harried by the O'Mores as he launches an offensive into Offaly and ...

...relieves the fort of Maryborough.