The greatest number of Irish songs ever published, over 1,000 in all, was collected, researched, edited and set to music by An tAthair Pádruig Breathnach / Fr Patrick A. Walsh (1848–1930), a Vincentian Catholic priest and an active cultural nationalist who is almost now a forgotten figure. . Published at politically significant times from 1904 to 1926, Breathnach’s songbooks influenced nationalist cultural thinking during the period, providing material for the de-anglicisation programme of the Gaelic League, disseminating patriotic songs in English during the War of Independence, and making bilingual song provision for schools as part of the nation-building of the new state.

Some 470 of these songs are in Irish and 530 in English. Drawn from oral, manuscript and printed sources, they were published in a sequence of cheap popular songsters and songbooks mainly by the Dublin firm of Browne & Nolan. Every song text was set to a melody in tonic solfa. Sales of these publications ran into the tens of thousands, and they would have a lasting influence on the oral tradition of both languages.

Pádruig Breathnach was born during the Famine in a largely Irish-speaking district near Carrick-on-Suir, Co Waterford. Having been educated locally and in the Catholic seminary of Maynooth, Co. Kildare, he was ordained a priest about 1873; most of his ministry was carried out in the cities of Cork and Dublin. He was interested in music and song from his youth, and, as an early enthusiast for the preservation and revival of the Irish language, he joined several Irish-language organisations before becoming a member of the new Gaelic League in 1893. As a young priest in Cork, he collected songs in Irish from his parishioners and on holidays in west Cork. More than 150 Irish-language songs in his collections, words and music, were collected in Cork and Waterford by himself or by his close associate Áine Ní Raghallaigh (1868–1942) of Macroom, a Gaelic League singing teacher.

In the early 1900s, when he himself was in his fifties, Breathnach was persuaded to begin publishing songs in Irish in penny songsters for schoolchildren. The success of his efforts led him to continue with similar songsters aimed at members of the growing Irish-language revival. The songsters were eventually collected into book form in 1913, and he went on to produce a series of further Irish-language songbooks for over a decade. Many of their songs were new, insofar as Breathnach selected verses by various authors and set them to music collected by himself or chosen by him from the published collections of Irish melody. Breathnach was also aware of the national value of the English-language songs of Ireland and by 1915 he had begun the publication of these songs, again in penny songster form and eventually in a hardback series of songbooks. His publishers advertised these as containing over 1,300 pages of song.