X:1 T:O'Reilly's Lamentation M:3/4 L:1/8 R:Air Q:"Rather Slow and Plaintive" N:"Very Ancient, Author & date unknown." B:Bunting - Ancient Music of Ireland (1840, No. 144, p. 106) Z:AK/Fiddler's Companion K:F (c/>B/)|(.A.F .A)(B/c/) (.B>.G)|(.E>.G) (F2 F) (3c/d/e/|f2 (.d>.f) (.e.c)|(.d=.B) (c2c) (3c/d/e| f2 (.d>.f) (.e.c)|(.A.c) (d2 d) (f/>d/)|(.c.A .F)(A/c/) (.B.G)|(.E>.G) (F2 F) (3c/d/e/| .f2 (d>f) (.e>.c)|((.A.c) .d)(d/e/) (f/e/)(f/d/)|(.c.A .F)(A/c/) (.B.G)|(E>G) (F2F)||
O'REILLY'S LAMENTATION (Uaill-Cuma Ui Ragallaig). AKA – "Caoine for O'Reilly," "Tuireamh Uí Raghallaigh." Irish, Slow Air (3/4 time). G Major (O'Neill): F Major (Bunting). Standard tuning (fiddle). One part. The melody was collected by Edward Bunting (1773–1843), educated as an organ and piano player in Belfast and renowned as the first systematic collector of Irish folk music. Bunting remarks (Ancient Music of Ireland, 1840, p. 92):
The O'Reilly, in commemoration of whom this melody was arranged, was Maolmordha, or Miles, sirnamed "The Slasher," probably son of Maolmordha Dha, or Miles "the handsome," who was "the Queen's O'Reilly" in the reign of Elizabeth. Miles "the Slasher" was colonel of horse in the army commanded by Lord Castlehaven in the wars which followed the rebellion of 1641, and was slain valiantly defending the bridge of Finea against Monro's Scotch, in 1644.—See Castlehaven's Memoirs.)
The fate of the battle is past
O'Reilly stood firm to the last
His friends round him lay
Yet he still kept the day
Till he fell to the ground
There his bosom all gored
And still grasping his sword
O'Reilly was found. ...[Bunting]
O'Sullivan gives Bunting's MS version in 4/4 time, though the collector's 1840 volume gave the tune in 3/4 time.
O'Reilly was a historical, if somewhat legendary, figure in Irish history. The standard (and rather brutal) tale  of his exploits goes:
Among the folk heroes of Cavan is Myles O'Reilly, better known as Myles the Slasher. In 1641, the whole of Cavan had fallen to the insurgents under Philip McHugh O'Reilly and Mulmore or Myles O'Reilly who styled himself sheriff of the county. Only two garrisons at Keelagh and Croghan continued to hold out. Sir Francis Hamilton had 200 foot and six horse, three barrels of powder and provisions for six months at Keelagh. Both castles became places of refuge for fugitive English and Scots settlers fleeing from Leitrim and west Cavan. The defense of the castles was hampered by the presence of 700 refugees at Keelagh and 120 at Croghan. Myles sent his father Edmund, to take the two castles. He was joined by a force of the O'Rourkes from Carrigallen and Ballinamore so that together they made up 2,000 men. Hamilton heard of their advance and to prevent them occupying Killeshandra town he had it burned to the ground. He knew that the insurgents could not face the cold of winter in the open.
In a skirmish near Keelagh castle, Edmund O'Reilly was repulsed and Loughlin O'Rourke and Brian O'Rourke were taken prisoners. They were promptly exchanged for Bishop Bedell, Protestant Bishop of Kilmore, his son and his son-in-law, Mr. Clogy, who were prisoners at Loch Uachtair Castle. To prevent the insurgents taking refuge in the woods around, Hamilton burned the country for a radius of three miles around the castle. In another skirmish Fr O'Rourke, a friar, was killed in his habit while leading the rebels and two important men, Owen O'Rourke and Philip O'Reilly, were captured and held as hostages.
When Myles O'Reilly heard of his father's failure to take the castles he withdrew from the siege of Drogheda and marched to Cavan. He was joined by a force from Leitrim and by 300 men under Robert Nugent of Westmeath. Once again the rebels were driven off after a skirmish at Windmill Hill near the town. Myles O'Reilly was so annoyed at his failure to take the castles that he went to Belturbet and had 60 English settlers who had been allowed to stay on in the town thrown from Belturbet bridge into the Erne. In revenge for this Sir Francis Hamilton went to Derewily on the Leitrim border with 100 foot and 30 horse. He surprised 60 natives in a wood there at dawn, killed 27 of them and hanged fourteen others.
The insurgents, who found it impossible to capture strong castles for want of artillery, decided to surround the castles and reduce them by starvation. By March 1642 supplies in both castles were running down. They had lost all contact with the outside world and were hopelessly abandoned. On 8 April, Sir James Craige died. His castle was wasted by disease – one hundred and sixty died of hunger and disease and the remainder were too weak to defend the castle. Hamilton was forced to take on the defence of both castles. A number of men were sent in turn each day to defend Croghan. They could not stay in the castle lest they take the disease. On 4 May the Irish were told of the plight of both garrisons by a fugitive called Barlow who fled from Keelagh to the enemy. They decided to make another attempt to take the castles. Two thousand men under Colonel Philip Mac Hugh O'Reilly drew up before both castles. They cut off the water supply from Croghan by throwing a dead dog and the body of a man into the well which supplied it. The inhabitants were dying of thirst. In Castle-Hamilton or Keelagh the position was little better. They killed their milch cows first, then their horses and dogs and finally were forced to eat hides of animals killed months before. The soldiers began to mutiny and six or seven of them fled to the enemy. Sir Francis himself was sick. He was forced to surrender and an agreement was drawn up between the O'Reillys and the O'Rourkes on one side and Sir Francis Hamilton, Sir Arthur Forbes, Master Bedell and Master Price on the other. The Irish agreed to let the garrisons go free to Drogheda and guaranteed them protection on the way. Sir Francis Hamilton marched out from Keelagh Castle on 15 June 1642. They marched away for Drogheda, with matches burning, banliers full, drums beating and colours flying, and under escort by the O'Reillys.
Bunting seems not to have associated the melody with Myles O'Reilly the harper, born about 1636, who lived in Killincarra, County Cavan. O'Reilly is credited with composing the original air "Lochobar" (the Scottish name coming from Allan Ramsay's song setting in his Tea-table Miscellany, "Farewell to Lochaber, Farewell to My Jean"); the melody was referred to as "The Irish Tune" in Thomas Duffet's New Poems, Songs, Prologues, and Epilogues, etc. (1676) [O'Neill, Irish Minstrels and Musicians, 1913, p. 59].