At Knocknacloy he had the center of his army protected by the hill, the right by a marsh, and the left by the river, so that, a flanking movement on Monroe's part being impossible, the Scottish general was forced to make a frontal attack. Under cover of the rearguard action at the pass, which caused both delay and confusion to Monroe's army, Owen Roe formed his men in order of battle. His first line was of four columns, with considerable spaces between them; his cavalry was on the right and left wings, behind this first line; while three columns more were drawn up some distance farther back, behind the openings in the front line, and forming the reserve. We should remember that not only was Owen Roe's army outnumbered by Monroe's, but also that Owen Roe had no artillery, while Monroe was well supplied with guns.
Meanwhile Monroe's army came into touch with Owen Roe's force, and the Scottish general opened fire with guns and muskets, to which the muskets of Owen Roe as vigorously replied. The Scottish artillery was planted on a hillock a quarter-mile from Owen Roe's center, and under cover of its fire an infantry charge was attempted, which was brilliantly repulsed by the pikemen of Owen Roe's army. A second attack was made by the Scottish cavalry, who tried to ford the river, and thus turn the left flank of the Irish army, but they were met and routed by the Irish horse. This was about six in the evening, and the sun, hanging low in the sky, fell full in the faces of the Scottish troops. Owen Roe promptly followed up the rout of the Scottish horse by an advance, making a sweeping movement from right to left, and thereby forcing Monroe towards the junction of two streams, where he had no space to move. At this point Owen Roe's army received a notable accession of strength in the form of four squadrons of cavalry, sent earlier in the day to guard against the possible approach of George Monroe from Coleraine.
At a signal from Owen Roe, his army advanced upon Monroe's force, to be met by a charge of the Scottish cavalry, instantly replied to by a charge of the Irish cavalry through the three open spaces in the front infantry line of Owen Roe's army. Monroe's first line was broken, and the Irish pikemen, the equivalent of a bayonet charge, steadily forced him backwards. It was a fierce struggle, hand to hand, eye to eye, and blade to blade. The order of Owen Roe's advance was admirably preserved, while the Scottish and English forces were in confusion, already broken and crowded into a narrow and constricted space between the two rivers. Finally the advancing Irish army reached and stormed the hillock where Monroe's artillery was placed, and victory was palpably won. The defeat of the Scottish and English army became an utter rout, and when the sun set more than three thousand of them lay dead on the field.
It is almost incredible that the Irish losses were only seventy, yet such is the number recorded, while not only was the opposing army utterly defeated and dispersed, but Monroe's whole artillery, his tents and baggage, fifteen hundred horses, twenty stand of colors, two months' provisions and numbers of prisoners of war fell into the hands of Owen Roe; while, as a result of the battle, the two auxiliary forces were forced to retreat and take refuge in Coleraine and Derry, General Robert Monroe escaping meanwhile to Carrickfergus. It is only just to him to say that our best accounts of the battle come from officers in Monroe's army, Owen Roe contenting himself with the merest outline of the result gained, but saying nothing of the consummate generalship that gained it.
For the next two years we see Owen Roe O'Neill holding the great central plain, the west and most of the north of Ireland against the armies of the English Parliamentarians and Royalists alike, and gaining victory after victory, generally against superior numbers, better armed and better equipped. We find him time after time almost betrayed by the Supreme Council, in which the Norman lords of Leinster, perpetually anxious for their own feudal estates, were ready to treat with whichever of the English parties was for the moment victorious, hoping that, whatever might be the outcome of the great English struggle, they themselves might be gainers. At this time they were in possession of many of the abbey lands, and there was perpetual friction between them and the ecclesiastics, their co-religionists, who had been driven from these same lands, so that the Norman landowners were the element of fatal weakness throughout this whole movement, willing to wound, and yet afraid to strike. While praying for the final defeat of the English parliamentary forces, they dreaded to see this defeat brought about by Owen Roe O'Neill, in whom they saw the representative of the old tribal ownership of Gaelic times, a return to which would mean their own extinction.
Matters went so far that the Supreme Council, representing chiefly these Norman lords, had practically betrayed its trust to the Royalist party in England, and would have completed that betrayal had not the beheading of King Charles signalized the triumph of the Parliamentarians. Even then the Norman lords hoped for the Restoration, and strove in every way to undermine the authority of their own general, Owen Roe O'Neill, who was almost forced to enter into an alliance with the Puritans by the treachery of the Norman lords. It is of the greatest interest to find Monroe writing thus to Owen Roe in August, 1649: "By my own extraction, I have an interest in the Irish nation. I know how your lands have been taken, and your people made hewers of wood and drawers of water. If an Irishman can be a scourge to his own nation, the English will give him fair words but keep him from all trust, that they may destroy him when they have served themselves by him."
On November 6, 1649, this great general died after a brief illness, having for seven years led his armies to constant victory, while the Norman lords, who were in name his allies, were secretly plotting against him for their own profit. Yet so strong and dominant was his genius that he overcame not only the forces of his foes but the treacheries of his friends, and his last days saw him at one with the Normans, while the forces of the Parliamentarians in Ireland were calling on him for help.
We sea, therefore, that for full eight years, from the beginning of 1642 to the close of 1649, Ireland had an independent national government, with a regularly elected Representative Assembly, and a central authority, the Supreme Council, appointed by that Assembly, with judges going circuit and holding their courts regularly, while the Supreme Council held a state of almost regal magnificence, and kept several armies continuously in the field. While Owen Roe O'Neill lived, that part of the army under his command was able not only to secure an unbroken series of victories for itself, but also to retrieve the defeats suffered by less competent commanders, so that at his death he was at the summit of power and fame. If regret were ever profitable, we might well regret that he did not follow the example of the great English commander, his contemporary, and declare himself Lord Protector of Ireland, with despotic power.
After his death, the work he had done so well was all undone again, in part by treachery, in part by the victories of Oliver Cromwell. Yet ten years after the Lord Protector's arrival in Ireland, his own work was undone not less completely, and the Restoration saw once more enthroned every principle against which Cromwell had so stubbornly contended.