The Fernaig manuscript (Scottish Gaelic: Làmh-sgrìobhainn Fheàrnaig) is a document containing approximately 4,200 lines of verse consisting largely of political and religious themes. The manuscript was composed between 1688 and 1693 by Donnchadh MacRath in Wester Ross and is notable for the author's unique orthography which is, like the more famous Book of the Dean of Lismore, based upon English, rather than Classical Gaelic, phonetics. Although the manuscript has been studied, "translated" in accordance with correct Gaelic orthography and republished – for the first time in 1923 by Calum MacPhàrlainn – it has been said that it has yet to be reliably interpreted.
In addition to the unusual spelling system used the manuscript is notable for several other reasons. It is the only record of Scottish verse which is similar in form and nature to that practised by the Munster poets at the start of the 17th century. It also contains religious poems which predate the composition of the manuscript by several centuries and have been described as the only extant examples of religious verse from that period as equivalent examples recorded following Culloden are very sparse. All other remaining records of 17th century Gaelic verse were committed to paper only after surviving for a hundred years or more as part of the oral tradition. The manuscript contains 59 pieces with 10 being of unknown authorship, 12 attributed to MacRath himself with a further 17 authors named as responsible for the rest.
Excerpt from the poem "Gillimichells ansr to ye ford lyns" (Gille-Mhicheal's Answer to the Foresaid Lines):
is trouh i cheile veg Ri Vlliam
Reine mūnnin and si toirse
Hreig i vi ri dūinoilis
is leish i būrris vi ri boist
No faickig eads cūndoirt ea
Snach burrine ea si toire
Seads loūyh chuirrig mulloid er
No Tih nach vūn da void