Here's my attempt. I may have got a few things wrong because I don't know
the context. It looks like a modern Irish prophecy.
> i mBretnaib, ní himargó,
> frisin ré sin ro theachtaig
> Saxain & slóg-Bretnaig.
> A cind deich mbliadan iar sin
> tinólaid, tenn in togail,
in Britain (no lie)
at that time took possession
the Saxons and the host-Britons (?).
Ten years after that
they assemble (severe the attack)
> Saxain is Bretain cen brón
> dochum nÉrenn a tinól.
> Fiche bliadan dó co tenn
> i rígi thuaiscirt Érenn
> i foirb in athar ór gein
the Saxons and the Britons without grief,
aimed towards Ireland is their assembly.
20 years, severly, he (?) [will be]
in [possession of] the kingdom of northern Ireland
in the estate of the father from whom he was born.