Situated about twelve miles west-by-north of Dublin, this ancient fortress of the Pale was the chief stronghold of the Kildare branch of the Geraldines. It was built by Maurice FitzGerald (the first of the great family to settle in Ireland) to protect the lands of Offaly, granted to him in 1176 by Strongbow in lieu of part of Wexford which King Henry wished to retain.

From the excellency of the twelfth-century masonry, the great keep, with walls some 8 feet in thickness, and the gate-house, are the best preserved parts of the ruin. The large corner tower and three round arches adjoining belong to the thirteenth century, while the fifteenth century is represented by an oblong tower, now used as the belfry of the Episcopalian Church. The rest of the buildings which connected these, now isolated, structures have almost entirely disappeared.

The fortress was surrounded on two sides by water, being at the junction of the River Lyreen, a tributary of the Liffey, and a smaller stream.

In 1248 we read that Luke, Archbishop of Dublin, erected the chapel of Maynooth into a prebend of St. Patrick’s Cathedral at the request of Maurice, second Baron of Offaly. This building, which was once the castle chapel, is now the parish church.

At the beginning of the fourteenth century Maynooth seems to have been the favourite residence of the FitzGerald family. John, the 1st Earl of Kildare, and Thomas, the 2nd Earl, both died there (1316 and 1328). The latter bequeathed the castle to his wife. It is described as being “built of stone, with numerous offices partly of stone, and two gates, one leading to the town, and the other to the garden.”

The castle was added to in 1426, and is said to have been “one of the largest and richest Earl’s houses in Ireland.”

In 1534 the Earl of Kildare, being Lord Deputy, was summoned to London, and appointed his son, Lord Offaly, Vice-Deputy in his absence. Upon a rumour that his father had been executed, Lord Thomas, who was very young, went into rebellion, and such nobles and chiefs as refused to join his standard he sent as prisoners to Maynooth.

A division of the English army, landing at Howth to raise the siege of Dublin Castle, was met by “Silken Thomas” with two hundred men. An engagement followed, in which Lord Offaly was victorious, and the survivors of the King’s troops were sent captive to Maynooth.

At this time the castle was splendidly fortified with men and ordnance.

Hearing that the whole English army was about to arrive, Lord Offaly left Maynooth in command of Christopher Paris, his foster-brother, and went into Connaught to raise forces.

In January, 1535, seven hundred men were sent from Dublin to burn Maynooth Castle. A skirmish took place, and although some of the rebels were slain, the royal troops retired.

The Lord Deputy, Sir William Skeffington, now collected his forces, and marched in full strength against the stronghold. The siege began on the 14th of March, and was continued until the 23rd.

Upon arriving at Maynooth, Sir William demanded the surrender of the castle, and offered free pardon and reward to all the garrison.

To this he only received a jeering reply, so planting his cannon to the north of the building towards the park he opened fire. The attack was varied north-east and north-west, but though this continued for over a week little damage was done, save destroying the battlements.

Towards the close of this time a letter was shot out of the castle to the Lord Deputy from Christopher Paris, offering to find means of letting the besiegers enter the castle for a certain sum of money and provision for the rest of his life.

Sir William Skeffington agreed to the terms, and upon the 22nd, a field-piece having been captured from the besiegers, the Governor made it an occasion for high revelry. Thus, while the men who guarded the outer battlements were sound asleep after their carouse, the King’s troops easily entered the castle by scaling-ladders early on the morning of the 23rd.

Sir William Brereton led the attack, but the resistance was very feeble, the drunken soldiers believing that the cry of “St. George! St. George!” was but a dream. Sir William hoisted his standard from the highest turret, so as to inform the Lord Deputy that the castle had been won.

Sir William Skeffington entered in the afternoon. The garrison consisted of thirty-seven persons. Two singers of the chapel were pardoned, at the intervention of Chief Justice Aylmer, on account of their sweet voices.

Twenty-five of the men were beheaded, and one hanged, outside the castle gate, and the principal heads placed upon the battlements. Amongst these was that of the Dean of Kildare. Paris was paid the sum stipulated for his treachery, but as he had forgotten to make his safety a condition, he was executed with the rest.

The Lord Deputy left a garrison in the castle and returned to Dublin.

Lord Offaly was marching to the relief of his stronghold with an army of seven thousand men when the news of its fall reached him. At this, most of his forces melted away, and the rebellion became rather a series of raids than regular warfare.

At last, Lord Thomas, tempted by a promise of pardon, surrendered himself, and was sent prisoner to England. Here, after some months of captivity, he and his five uncles were beheaded at Tyburn.

There is a tradition that the last evening “Silken Thomas” ever spent at Maynooth he played the harp under the venerable yew which is now enclosed in the grounds of St. Patrick’s College.

A bill of attainder was passed in 1536 against the Earl of Kildare and his heirs; and Maynooth, being forfeited to the Crown, became a King’s castle. It seems to have been a favourite residence of the Lords Deputy at this time.

In 1552 Edward VI. restored Gerald, 11th Earl of Kildare, to his title and estates. His widow lived at Maynooth until her death; and it was in the castle garden that Lord Delvin was first approached by the Earls of Tyrone and Tyrconnell to join the insurrection in 1606. In a letter written by the Countess of Kildare she expresses her regret for such an occurrence.

After the death of the 14th Earl in 1612, Maynooth Castle seems to have fallen into a state of dilapidation on account of his son’s minority. It was restored by his guardian, the great Earl of Cork, who placed an inscription over the gateway recording its restoration, and bearing the date 1630.

In 1629 we hear of the Earl’s title deeds being preserved in the Council House, which was a stone building that stood on the site now occupied by the President’s house of St. Patrick’s College. It was removed about 1780. The doorway is still preserved in a school of the town, and the council table, bearing the date 1533, stands before the Duke of Leinster’s residence at Carton.

The 12th Earl of Kildare lived at Maynooth until civil war broke out in 1641. Shortly after hostilities began the castle was plundered and the valuable library destroyed.

In 1643 Captain Michael Jones, under the Marquis of Ormond, held possession of the fortress; and in 1644 the Earl of Kildare asked for powder and men to increase its defence, he having taken down the spouts to make bullets.

In 1647 General Owen O’Neill sent a detachment from Trim, which carried the castle by assault. Twenty-six men of the garrison and some officers were hanged, and the fortress dismantled.

The next Earl lived chiefly at Kilkea Castle, and Maynooth gradually fell into decay.

In 1707 Robert, 19th Earl of Kildare, wished to restore the building, but finding it too dilapidated he decided to enlarge Carton House instead.

Houses were subsequently built among the castle ruins, and these were removed by the Duke of Leinster in 1848, and the space round planted and enclosed.