By the 5th century A.D. the sept held territory in and around the modern barony of Oneilland, County Armagh, Northern Ireland, on the southwest shore of Lough Neagh.

When Edmond Mortimer arrived in Ireland in 1380 as Lord Justice, the chief O'Hanlon was recorded as amongst the righdamhna (those eligible to become a tanist, or heir-apparent, of an Irish kingdom) that were required to pay their court to him.

"[2] The northern roads converged on the modern-day village of Tandragee; the approaches from Dublin and the English Pale had to force the Gap of the North, and the chieftain's stronghold adjacent to Forkill at Mullagh.

He was unable to found a settlement as required, and had his grant revoked, with Sir Eochaidh "Oghy" O’Hanlon of Tanderagee able to reassert control over south Armagh.

After the Battle of the Boyne, those holding the O'Hanlon and Hanlon names diverged socially, some assimilating into colonial Irish society and others staying rooted to their Gaelic past.

A real-life Robin Hood, Redmond robbed the English settlers, extorted protection money from the Scots, and was adored by the largely Catholic peasantry.

A letter from the era states that his criminal activities were bringing in more money than the King's revenue collectors, and therefore the outlaw Count was easily able to bribe military officers and public officials.

He was eventually murdered in his sleep by his foster brother and close associate Art MacCall O'Hanlon at Eight Mile Bridge near Hilltown on 25 April 1681.

Aodh Buide O'Hanlon held the largest tract, 2,045 acres stretching from the northern slope of Sliab Gullion northwest toward Belleeks at the edge of the Fews.

At a dinner in Curran's honour, held at the Whitecross Hotel in Margaret Street, Hugh was lauded for efforts made on behalf of the Patriot-lawyer's election.

There, Hugh III founded Ireland's system of local government through a pilot program for Newry in the form of a Westminster bill, for "Better Lighting, Watching, Cleansing and Paving".

Other sons of Hugh, Jr. included Pringle, who served in the First Bengal Cavalry; another, Edward, died in colonial service at Rangoon, in the British East Indies.

Included among those who also passed into Irish colonial society was the Colonel Ó Hanlon of 1821, who petitioned to resume Sir Eochaidh O'Hanlon's honorary position as Royal Standard Bearor to the King (or Queen) "north of the river Boyne".

Whatever their history, the lands did not remain in Ó Hanlon hands for long: the Mountnorris estate shortly afterwards became the property of Francis Annesley, 1st Viscount Valentia (an Englishman).

Daire, common ancestor to the septs O’Hanlon, MacMahon, Maguire and McCann offered Saint Patrick a church site lower down on the hill on which the chieftain's rath was located.

The ancient writings from the 5th century onwards were compiled in 1632–1636 by a Franciscan friar, Michael O'Clery, into a volume which became known as the Milesian genealogies and survived to modern times.

The Ua'h-Ainlighe sept has its roots in the ancient recesses of the Roscommon Area and is associated with the tribe of Cinel Dobtha, or O'Hanley of Doohey Hanley, to which also belong the MacCoilidh family The MacCoilidh family, whose name was anglicized to Cox in the early years of the seventeenth century, were hereditary custodians of Saint Berach crosier, and were considered as 'lay abbots' of Kilbarry.

The first mention of the name O’Hanlon (Ui Anluain) was in the first millennium, in the year 938 in the Annals of the Four Masters, which states: M983.6 Flaithbheartach Ua hAnluain, lord of Ui-Niallain, was treacherously slain by the Ui-Breasail.

By 1004 The O’Hanlons are the de jure rulers of territory beginning at the townlands supporting the bishop at Armagh and stretching in an arc south and east to the mountains overlooking Viking settlements on Carlingford Lough.

The over-kingdom of Airgialla, which had gradually come under the domination of the Cenel Eoghain and pushed southwards, shrunk further in the advance of the Normans in the late 12th and early 13th century.

The O'Hanlons lost the town of Dundalk in the south of Airthir (modern day County Louth), but were allowed to stay as paying tenants.

Following the Norman invasion of Ireland, "The O’Hanlon" is listed among the Ulster chieftains to whom the English King Henry III appealed for aid in his war against the Scots.

Fleming instructed the clergy to post "the excommunication and interdict on Sunday and festivals in all their churches and market places, while clad in albs and stoles, with cross erect, bells and candles, until further order".

At the same time he warned "all, English and Irish, within his diocese to refrain from conversation, eating or drinking with the above-named persons, and desired that they should not be sold bread, beer, salt or any of the necessities of life".

After ascending to the throne in 1558, Queen Elizabeth I proclaimed herself head of the Irish Church (the Act of Supremacy), and went about replacing the "Old English" clergy and administrators with newly appointed Englishmen.

Against the odds, the Gaels marched South through enemy territory to meet the Spanish, and arrived in a matter of weeks with 12,000 men to lay siege to the English at Kinsale.

1599 Dymmock's 'Treatise on Ireland' notes that Sir Oghie O'Hanlon, on 28 April 1599, could muster two hundred foot and forty horse for the Earl of Tyrone.

In County Armagh, the sept regains Tandragee Castle for a few years, until the Lord Protector, Oliver Cromwell, arrives to put all Ireland down.

Dispossessed but remaining in the southern highlands of their former homeland, the O’Hanlons take to a life of crime against the English colonial administration, its colonists, and their collaborators among the former Gaels, now Irish.

An Irish Robin Hood or Rob Roy MacGregor coming to the rescue of a fair maiden and her distressed fiancée, as her chastity (and his property) were threatened by a debauched son of the Anglo-Irish colonial elite ruling south Armagh.