Elliott Lash wrote:
> BB

> Cath argethis (?)   is cath conaig

The second word is 'argetruis' (the genitive of the placename Airgetros; 
see Cath Crinna §11). The zig-zag above the 't' is not a mark of 
lenition, but rather a 'u'. It takes this form only when it is written 
superscript. What is more, when a vowel is written superscript it is to 
be read as vowel+r or r+vowel (so here it = 'ru').

(Another vowel which changes its shape when written superscript is the 
'a' - which is written like an 'n'. Indeed, now I come to think of it, 
there is a vertical zigzag which is used superscript for 'e+r': it looks 
like a little flame.)

> rof*orbert rois petaig 

The contraction over the 't' in the first word is probably not for 'er' 
in this case, but rather '(e)ar'; still, you can't be really tell what 
it stands for till you have translated the whole thing: certainly the 
default reading is as you have it.

The final word starts with 'f', not 'p' (it's just that the 'e' is 
jammed up against it).

> cath ata cro cru sligid 

There is a mark of lenition over the 't'; so 'atha'. As this line is a 
syllable short, we should probably insert '[for]' before 'sligid', 
following Lec.

> robo du dothebaig

As each line must end in a disyllable, the last 'word' has to be split 
up: 'do debaig'. I can understand why you read 'th', but it is a 'd' 
jammed up against the following 'e' (the horizontal bar would be 
straighter in a 't'), and the lenition mark is just a smudge on the MS I 
think. (Cf the reading 'deabaig' in Lec.)

> Lecan
> Cath airged rois is cath conaig

The placename 'Airgedrois' looks like two words in the MS, but we know 
from our translation of Cath Crinna §11 that it is one.

> rof*oirbeart rus feadaig.

I suspect the dot over the 'f' is a discolouration of the MS rather than 
an ink mark. It is hard to tell.

> Cath atha cro cru for sligid
> robo du ruideabaig

Again the last word should have only two syllables. (Each line in this 
metre ends in a disyllable.) The final word is clearly 'deabaig'. I 
think that the preceding three minims stand for 'in' rather than 'ui' - 
note that there is no serif at the top of the third minim (which 
suggests that it is the second stroke of an 'n'). This looks like the 
definite article (or the nasalising preposition 'i n-'); which leaves 
the preceding 'r' isolated. I read the 'r' as belonging with the 
preceding 'du'; despite the reading in BB.


So I would suggest:
BB
Cath Argetruis is cath Conaig
ro-forbart rois fedaig
cath Âtha Crô, crû [for] sligid
robo dû do debaig

Lec.
Cath Argedrois is cath Conaig
ro foirbeart rus feadaig
cath Âtha Crô, crû for sligid
robo dûr in deabaig

Thanks for getting us started Elliott. And now for the translation. 
There seem to be some peculiar forms here. I can't get the case forms of 
in 'rois', 'fedaig' and 'debaig' to make sense without assuming 
something irregular is going on. But I am hoping someone can explain them.

Neil