Four 'Irish' mercenaries in Stettin during the Thirty Years War, 1632.

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Kurtze
Beſchreibung / deß auß Irrland / Königl. Ma
jeſtat in Schweden ankommenten Volcks/von dero Lands
Art / Natur / Waffen vnnd Eygenschafft.
__________________________________________________________________________________________________________________
In ſolchem Habit Gehen die 800 In Stettin angekommen Irrlander
oder Irren.
Four 'Irish' mercenaries in Stettin during the Thirty Years War

Es iſt ein Starckes dauerhafftigs Volck behilft ſich mit geringer ſpeiß hatt es nicht brodt ſo Eſſen ſie
Würtzeln Wans auch die Notturfft erfordert können ſie des Tages Vber die 20 Teützſcher
meilweges lauffen, haben neben Muſqueden Ihre Bogen vnd Köcher vnd lange Meſſer.

Possibly 'Irish' from the western isles of Scotland, see The Scots by George Gush.
Held by the British Library
Reference: Travels to terra incognita : the Scottish Highlands and Hebrides in early modern travellers' accounts c. 1600 to 1800 by Martin Rackwitz

Kurtze Beschreibung, for example, glorifies the international troops of the Swedish army, and so draws on the technique used to present both Gustavus Adolphus and Bethlen Gabor. This glorification is creative and bold in the radical propagandists’ presentation of the Irish, who are praised in Kurtze Beschreibung as the most hardy and resourceful of the Swedish soldiers. This is conveyed in the illustration of the broadsheet which portrays four Irishmen, one of which is barefoot. The lack of shoes is not a sign of poverty, but an indication that he is capable of enduring difficult conditions. The four Irish troops stand confidently on a grassy knoll, and carry different weapons. Two of them carry a bow and arrow, while the third rests a musket on his shoulder. This image suggests readiness for battle and skill in different arms. Behind the men are rows of soldiers marching forward in orderly lines. This conveys a sense of discipline and below the image is the broadsheet’s only line of text, designed to strengthen the case that the Irish soldiers are able to survive in harsh circumstances.
The text immediately under the image reads:
Es ist ein Starckes dauerhafftigs Volck behilft sich mit geringer speiß hatt es nicht brodt so Essen sie Wurtzeln, Wans auch die Notdurfft erfordert konnen sie des Tages Vber die 20 Teutzscher meilweges lauffen, haben neben Musqueden Ihre Bogen vnd Kocher vnd lange Messer. (Kurtze Beschreibung, line 1)
As Harms points out in his analysis of the broadsheet, the depiction of the Irish as willing to scour the earth for food could also be an attempt to present them as modest and as a people who show no sign of the deadly sin of gluttony or immoral self-indulgence, remaining instead in a state of innocence.²⁹³ This echoes descriptions of Gustavus Adolphus himself, who is called time and again a paradigm of virtue, an outstanding role-model, and, as Tschopp demonstrates in her work on pro- and anti-Swedish propaganda, even superior to figures of the Bible. These portrayals are all intended to inspire the audience’s respect and admiration for the Swedish King and his forces. [Continued in the broadsheet: Auß Lap vnd Liefflandt]

293 Harms Feindbilder, p. 151.
Source: pp.160-162, Foreign Heroes and Catholic Villains: Radical Protestant Propaganda of the Thirty Years’ War (1618-1648) by Darren Paul Foster, University of Exeter thesis