The Irish National Anthem "The Soldier's Song" is highly situational, based on the OTL events of the 1916 Easter Rising, the War of Independence and the Civil War. In a TL where, for instance, there was no WWI and Ireland achieved Home Rule (relatively) peacefully it definitely wouldn't be the national anthem and indeed would never be written at all.
When boyhood's fire was in my blood
I read of ancient freemen,
For Greece and Rome who bravely stood,
Three hundred men and three men;
And then I prayed I yet might see
Our fetters rent in twain,
And Ireland, long a province, be
A Nation once again!
A Nation once again,
A Nation once again,
And Ireland, long a province, be
A Nation once again!
And from that time, through wildest woe,
That hope has shone a far light,
Nor could love's brightest summer glow
Outshine that solemn starlight;
It seemed to watch above my head
In forum, field and fane,
Its angel voice sang round my bed,
A Nation once again!
A Nation once again,
A Nation once again,
And Ireland, long a province, be
A Nation once again!
It whisper'd too, that freedom's ark
And service high and holy,
Would be profaned by feelings dark
And passions vain or lowly;
For, Freedom comes from God's right hand,
And needs a Godly train;
And righteous men must make our land
A Nation once again!
A Nation once again,
A Nation once again,
And Ireland, long a province, be
A Nation once again!
So, as I grew from boy to man,
I bent me to that bidding
My spirit of each selfish plan
And cruel passion ridding;
For, thus I hoped some day to aid,
Oh, can such hope be vain?
When my dear country shall be made
A Nation once again!
Thomas Osborne Davis.
He was a Protestant, but preached unity between Catholics and Protestants. To Davis, it was not blood that made a person Irish, but the willingness to be part of the Irish nation. Although the Saxon and Dane were, Davis asserted, objects of unpopularity, their descendants would be Irish if they simply allowed themselves to be.