[2] He assuredly authored twelve poems out of a collection of twenty-five broadsides arguing against Queen Mary as a part of the Kings Party's political campaign, which collectively are known as the "Sempill ballads".
[5][6] Anonymous printed ballads such as The tressoun of Dumbertane, Robert Lekprevik, Edinburgh (1570), have been attributed to Sempill.
The Tressoun describes Lord Fleming's failed ambush of the English commander William Drury at Dumbarton Castle.
Modern editions of Sempill are: Sege of the Castel of Edinburgh, a facsimile reprint with introduction by David Constable (1813); The Sempill Ballates (T. G. Stevenson, Edinburgh, 1872) containing all the poems; Satirical poems of the Reformation (ed.
James Cranstoun, Scottish Text Soc., 2 vols, 1889-1893) with a memoir of Sempill and a bibliography of his poems.