[3] Before he completed his studies, however, he emigrated in 1842 with members of his family, initially to Quebec,[1] but ultimately to Missouri in the United States of America (a migration perhaps occasioned by the death of his father).

[3] A year later, his health having improved, O'Hanlon offered his services to the Archdiocese of Dublin,[3] and became a curate in the parish of Saints Michael and John.

[3] O'Hanlon's best-known work remains his hagiography, in particular his Lives of the Irish Saints, which organizes its chronicles by feast day, from January 1 to December 31.

[5] In addition to this magnum opus O'Hanlon published many works on individual saints, although he mostly re-used these articles and pamphlets in his Lives, often verbatim.

[4] As a work of hagiography, the Lives of the Irish Saints has been surpassed by modern scholarship, but it remains a treasure trove of local information and tradition.

[6] The collected works of Lageniensis centre on a long poem in Spenserian stanza, "The Land of Leix" and a series of lays recounting stories from Irish mythology.

[4] O'Hanlon was a strong believer in the importance of topography, or the study of place, which is evident in his praise of the Ordnance Survey, for whom he advocated a government grant to employ artists to record local features.

During that period there was a great deal of agitation and unrest in Ireland, both by moral and political activists, and by violent societies such as the Whiteboys and the Rockites.

O'Hanlon recorded his early impression of the Ballykilvan evictions in 1828[4] and as a teenager attended Daniel O'Connell's meeting on the Great Heath in 1836.

He attended the House of Commons in London in 1893 for some of the debates about Home Rule for Ireland, of which he was a proponent, and admired Charles Stewart Parnell, as well as William Gladstone.

When he collected his poetical works as Lageniensis, he addressed the dedication to Lady Aberdeen, whose husband had served as Lord Lieutenant of Ireland and had just been appointed as Governor General of Canada, both viceregal positions.

At his Golden Jubilee his parishioners and fellow priests recognized his pastoral work, his patriotic advocacy or Irish national interests, and his extensive writings.

Finally, tribute was paid to O'Hanlon by none other than James Joyce, in the Nausicaa episode of Ulysses, where his activities in the St. Mary Star of the Sea church counterpoint Leopold Bloom's observation of Gerty McDowell on the nearby Sandymount Strand: "and the blue banners of the blessed Virgin's sodality and Father Conroy was helping Canon O'Hanlon at the altar".