.i. Conall mac Suibne romarb in tAed Slane oc Loch Semtide.  Aed Gustan comalta Conaill 
is e rodmarb.  Is e didiu romarb Aed Slane no Buide ri Teatfa 7 Oed Ron ri o Failgi isin n-
enlo, int Aed Gustan.

Thanks, Neil. I have -- 
    that is, Conall mac Suibne who has killed Aed Sláne at Loch Sewdy.  Aed Gustán, Conall's 
foster-brother, it is he who has killed them.   It is he then who has killed Aed Sláne or Buide 
king of Tethbae and Aed Rón king of Uí Fhailgi  on the same day, Aed Gustán. 

notes --  

The story is a bit confusing as to who killed Aed Sláne here, but the other texts are clearer.
rodmarb -- perfect of 'marbaid' (kils) with relative infixed 3rd plural pronoun
isin n-enlo --  isin + oen + laa --  on the one day
I am not sure I used all the conventional spellings of the names.

There was a discussion of this incident on this list in April 2010 
under the heading 'Cú 7 Cethen'. 
Comments welcome, Liz

>Silva Gadelica 75.5f:
>.i. Conall mac Suibni issé ro marb Aed sláine oc loch semdidhe. Aed gustán 
>comalta Conaill is é ro marb Aedh buidhe rí Teatfa a mbruidin dá choco ocus
>Aedh róin rí ua Foilghe i noenló.
>YBL 869d lie 46f:
>.i. Conall iarum mac suib-- ro marb aed sl-- (with subscript 'i' added
>later) oc loch semdidi. Aed gustan comalta Conaill is é ro marb Aed Buidi
>rí Tefa (with superscript 'th' added later) a mbruidin dá choca 7 Oed Roin
>rí .h. Failge isin n-oenlo sin