I suspect this is what Krystian is after, recorded on 'Belt of the Celts' (1978):

RORY O'MOORE
(Samuel Lover)

On the Green Hills of Ulster the White Cross waves high
And the beacon of war throws its flames to the sky
Now the taunt and the threat let the cowards endure
Our hope is in God and in Rory O'Moore

Do you ask why the beacon and banner of war
On the mountains of Ulster is seen from afar
'Tis the signal our rights to regain and secure
Through God and our country and Rory O'Moore

On the Green Hills of Ulster the White Cross waves high
And the beacon of war throws its flames to the sky
Now the taunt and the threat let the cowards endure
Our hope is in God and in Rory O'Moore

And his country, his kindred, his faith would abjure
We'll strike for old Ireland and Rory O'Moore

For the merciless Scots with their greed and their swords
With war in their bosoms and peace in their words
Have sworn the bright light of our faith to obscure
But our hope is in God and in Rory O'Moore

Oh lives there the traitor who'd shrink from the strife
Who would add to the length of his forfeited life
And his country, his kindred, his faith would abjure
No we'll strike for old Ireland and Rory O'Moore

On the Green Hills of Ulster the White Cross waves high
And the beacon of war throws its flames to the sky
Now the taunt and the threat let the cowards endure
Our hope is in God and in Rory O'Moore

And his country, his kindred, his faith would abjure
No we'll strike for old Ireland and Rory O'Moore