How the story survives

No one has the Táin as its first tellers told it. Kinsella opens his Introduction by saying that much of early Irish literature has been lost, and that much of what survives is contained in a few large manuscripts made in medieval times. The Táin comes down in three of them.

The three manuscripts

The oldest is Lebor na hUidre, familiarly known as the Book of the Dun Cow. It was compiled in the monastery of Clonmacnoise in the twelfth century. It holds part of the earliest known form of the Táin Bó Cuailnge, in what Kinsella calls a badly flawed and mutilated text.

Another partial version of the same early form is in the Yellow Book of Lecan, a manuscript of the late fourteenth century. It is flawed too. Between them these two give the main body of the Táin that Kinsella uses for chapters II to XIV.

The third is the Book of Leinster, also twelfth century. It carries a later form of the Táin, four centuries younger than the earliest, and the story survives in it complete. Its author or compiler took pains to produce a consistent and integral narrative. Kinsella takes from it the motive for the invasion, which is chapter I.

How old the story is

The manuscripts are late. The story is older. Kinsella says the language of the earliest form is dated to the eighth century, and some of the verse may be two centuries older than that. Most Celtic scholars hold that the Ulster cycle, like the rest of early Irish literature, had a long oral existence before monastic scribes gave it a literary shape and a few traces of Christian colour.

The state of the early text

Kinsella chose the earlier version over the complete one, and he is plain about what that cost. The early text is the work of many hands and in places is little more than the mangled remains of miscellaneous scribal activities. There are major inconsistencies and repetitions among the incidents. On occasion the narrative withers away into cryptic notes and summaries. Glosses, comments and wholesale interpolations from other sources have been added, in some cases over erased passages of the original. Frank O'Connor, whom Kinsella quotes, says the Cattle Raid has been rendered practically unintelligible.

His reason for putting up with this is the compiler of the Book of Leinster. Kinsella says that compiler had a generally florid and adjectival style, running at times to an overblown decadence, and that he preferred to give an idea of the simple force of the story at its best.

Where the manuscripts break down

Kinsella's notes record several places where a manuscript gives out.

• The Lebor na hUidre version ends in chapter X with the episode of Mann, whom Cúchulainn hurls at a standing stone and bursts asunder. Kinsella omits the episode, notes that Thurneysen lists it among the interpolations, and says the story continues in the Yellow Book of Lecan.
• In chapter XI the Yellow Book of Lecan breaks down abruptly in the combat of Ferdia and Cúchulainn. The episode is disposed of in a further 124 lines, 25 of prose giving fragments of the action and 99 of verse. From there Kinsella adopts the Book of Leinster.
• Kinsella calls the Ferdia combat an interpolation of not earlier than the eleventh century, a compendium of elements used in earlier episodes. Someone later wrote a note in the manuscript at this point, calling the writer of that section "a choice writer".
• A fragmentary manuscript in Trinity College, Dublin, listed as H.2.17, gives a later version of one episode in chapter VI. Kinsella draws two phrases from it.

The story found again

Kinsella's own first tale in the book is about this problem. The poets of Ireland gather around Senchán Torpéist to see if they can recall the whole Táin, and they all say they know only parts of it. Senchán's son Muirgen goes east to look for it. He sits down at the gravestone of Fergus mac Roich and chants a poem to it as though it were Fergus himself. A mist forms around him, he cannot be found for three days and nights, and Fergus appears and recites him the whole Táin, from start to finish.

Kinsella adds that some say the story was told to Senchán himself, after he fasted to certain saints of the seed of Fergus. He remarks that this seems reasonable. His note dates the tale to the ninth century and gives it as an anecdote from the Book of Leinster.

The scribes' last word

The Book of Leinster text ends with two scribal notes, which Kinsella gives at the close of his notes. The first is in Irish. It is a blessing on everyone who will memorise the Táin faithfully in this form, and not put any other form on it. The second is in Latin, and it is the scribe's own opinion of what he has just copied. It disclaims the story, calling it fantasy, devilish lies, poetical figments and entertainment for idiots. He copied it anyway.