[Errigal]

Originally Posted by Sektor

I'm very interested in this problem,and I'm wondering,was there a Monarchist idea,amongst the Irish nationalists???

Yes. Arthur Griffith advocated a return to the dual monarchy which existed until 1800. His model was Austro-Hungary.

From Wikipedia:

Most historians opt for 28 November 1905, as a founding date because it was on this date that Griffith first presented his 'Sinn Féin Policy'. In his writings, Griffith declared that the Act of Union of Great Britain and Ireland in 1800 was illegal and that, consequently, the Anglo-Irish dual monarchy which existed under Grattan\'s Parliament, and the so-called Constitution of 1782 was still in effect. Its first president was Edward Martyn.
The fundamental principles on which Sinn Féin was founded were outlined in an article published in 1904 by Griffith called the Resurrection of Hungary, in which, noting how in 1867 Hungary went from being part of the Austrian Empire to a separate co-equal kingdom in Austria-Hungary. Though not a monarchist himself, Griffith advocated such an approach for the Anglo-Irish relationship, namely that Ireland should become a separate kingdom alongside Great Britain, the two forming a dual monarchy with a shared monarch but separate governments, as it was thought this solution would be more palatable to the British. However, this idea was never really embraced by later separatist leaders, especially Michael Collins, and never came to anything, although Kevin O\'Higgins toyed with the idea as a means of ending partition, shortly before his assassination.