From The Irish Times:

https://www.irishtimes.com/opinion/letters/shakespeare-and-an-irish-tune-1.545410?mode=amp

Sir, – In "Wherefore art thou, Irish rat?", (Weekend Review, August 25th, 2012), Fintan O'Toole did not need to go back as far as Edmond Malone (1741–1812) to explain Shakespeare's "Calen o custure me". Malone was on the right track with "Cailín óg a stór", but it is a syllable short of the English form. When not shortened to "Callino", the title is spelt fairly consistently in literary sources and in lute and keyboard manuscripts, dating from 1582 to 1667: "Callin o custure me", "Calen o custure me", "Callino casturame", "Callino Castore me", and is also shortened to "Callino". The title remained relatively stable because it was sung as a chorus to the second four bars of each eight-bar line in the tune.

The original Irish was "Cailín ó chois tSiúire mé" ("I am a girl from beside the [river] Suir"), as the Irish scholar Gerard Murphy pointed out in 1939.

He noted that it occurred as Cailín ó chois tSiúire, the title of a piece of harp music, in Mealltar bean le beagán téad, a 17-century Irish poem. The title/chorus passed into Scottish Gaelic, in which it is found as the chorus of a walking song. Naturally, the Suir meant nothing to speakers of Scottish Gaelic, and the chorus became "Chailìn òg an stiùir thù mise" ("Little girl will you guide me"), or "Chailìn òg an stiùrmachaì" ("The helmsman's little daughter").

Distant descendants of Cailín ó chois tSiúire mé are the airs of The Newry Highwayman (New Lynn originally) and The Butcher Boy, both Irish versions of English traditional songs. The Croppy Boy, by "Carroll Malone" (Dr William B McBurney), first published in 1845, is sung to a version of the original air. This song was republished in 1858 in a collection that included a transcription of Callino from the Ballet Lute Book in Trinity College. The two were not associated in any way, but someone subsequently noticed that the words would fit the tune, and put them together.

Given the subtle references to Ireland in Henry IV, Shakespeare is likely to have known that the song was Irish in origin, but to most of his contemporaries it was just another foreign title. For example, John Davies of Hereford wrote in The Scourge of Folly (ca 1610): ". . . like the burden of the song Call'd Callino,/Come from a forraine Land,/Which English people do not understand." Ironically, the Callino Callino Callino Castore Me published in London in 1667, and subtitled An Irish Tune, is a different piece of music.

It has been suggested that the appearance of Cailín ó chois tSiúire mé in London owed something to the frequent presence at the Elizabethan court of Thomas Butler (1533–1614), 10th earl of Ormond, the famous "Tom Duff", who had been reared and educated with the future Edward VI, and who was very close to Elizabeth I. Besides the complement of professional musicians expected of a Tudor aristocrat, Ormond also had a famous Irish harper in his service, "Blind Cruise", and Cailín ó chois tSiúire mé is said to have been a harp tune in Mealltar bean le beagán téad. – Yours, etc,

SEÁN DONNELLY,

Decies Road,

Ballyfermot,

Dublin 10.