Was Yeats' "Second Coming" Based on an Earlier Poem?

I was going through some old books earlier this evening, and came across a poem called "Christmas: 1915," by a poet named Percy MacKaye, that concludes with the following lines:

Christ! What shall be delivered to the morn
Out of these pangs, if ever indeed another
Morn shall succeed this night, or this vast mother
Survive to know the blood-spent offspring, torn
From her racked flesh? -- What splendour from the smother?
What new-wing'd world, or mangled god stillborn?

Now, I'm not a Yeats scholar by any means, but this sounds very similar from a thematic standpoint to the famous final lines of Yeats' "Second Coming":

The darkness drops again but now I know
That twenty centuries of stony sleep
Were vexed to nightmare by a rocking cradle,
And what rough beast, its hour come round at last,
Slouches towards Bethlehem to be born?

The thematic similarities are unmistakable. Yeats' poem, as I understand it, was written in 1919. MacKaye's appeared in an anthology, A Treasury of War Poetry: British and American Poems of the World War, 1914 - 1917, that was published by the Houghton Mifflin Company in 1917. It seems plausible to me that Yeats might have encountered this poem two years before his own.

If the possible link between these poems is common knowledge, please forgive my bringing it up. But Mackaye's poem, though a very fine one, seems obscure enough to me that I believe it's possible no one has ever noticed this connection. I'd be interested in others' thoughts on this.

It was based on an earlier poem, though I am not sure if this is the one. I know he originally drafted a version, making more allusion to contemporary events, but dismissed it for the final "prophetic" style later to become "the Second Coming".

Would Yeats have taken inspiration from a war poem anyway? In one of his letters he speaks very negatively on the cannon of war poetry and its readers: "there is every excuse for him [Owen], but none for those who like him."

The inspiration for The Second Coming was as I understand it the Bolshivic revolution and the coming of communism.

Hi Michael,
It is true that Yeats was very dismissive of war poetry and it is unlikely that he would have taken inspiration from this poem. From a stylistic viewpoint, the major similarity I note is on the third line of the piece you quoted by Yeats, but I think that even this is far-fetched. It was rightly noted that Yeats's poem was heavily influenced by the Bolshevik revolution, but it is also heavily nfluenced by his system of gyres that were being unveiled to him at this same time through his wife George. To draw comparisons between the two poems would be to force them.
Mark