The tranche also includes the Yeats family library
The Government has bought letters and manuscripts belonging to WB Yeats and James Joyce.
The Arts Minister Heather Humphreys approved extra funding of over €500,000 to the National Library of Ireland (NLI) for the acquisition.
It features a significant number of manuscripts from the family of WB Yeats - including a collection of 10 signed letters, and a postcard to Yeats from James Joyce.
In the collection of letters to Yeats from Joyce, the men discuss Joyces's literary work - including 'Exiles', 'Dubliners' and 'Ulysses'.
The letters also discuss Yeats's work, as well as a typescript copy of Joyce's letter to Lady Gregory - dated November 22nd 1902 -on the eve of his departure from Ireland, sent by her to Yeats.
The letters span almost 24 years of correspondence.
In one of the last of the letters, Joyce expresses his gratitude to Yeats as 'it is now thirty years since you first held out to me your helping hand.'
The second key element of the acquisition is the 'Dream Diary' of Yeats's wife, George.
It lists dates, times, and location of sleeps with detailed accounts of her dreams.
Large portions of the diary are in the hand of WB Yeats - including a series of questions with answers by George.
The acquisition also includes the Yeats family library which will join WB Yeats's personal library, already at the NLI.
Included in this are books of the Yeats family, as well as a significant collection of Cuala Press material.
Minister Humphreys said: "This is an incredible collection of material, which will add greatly to the existing Yeats exhibition at the NLI, which already attracts over 70,000 visitors per year.
"The letters between Yeats and Joyce in particular are unique, offering an exceptional insight into Joyce's work and shining a light on the long friendship between these two literary giants."
Speaking on behalf of the Yeats family, Caitríona Yeats added: "I am delighted that the National Library of Ireland has been able to add to their Yeats collection.
"This would not have been possible without the generous extra funding approved by Minister Heather Humphreys.
"The additional funds have allowed the purchase of the Dream Diary, thereby completing the set, the remaining Yeats family books which will now become part of the previously donated WB Yeats library, Cuala Press material (both original and modern) and the James Joyce letters."
The collection was unveiled at a special reception at the NLI - attended by Minister Humphreys and members of the Yeats family.