In Nov1823 O'Donovan broke up his school, and removed to Dublin, to his brother " Leeum Vlaaclee " (William, of Dublin), who had given up his farm in Ballarourach some time before, and secured a situation in a merchant's shop in the metropolis.  Here he attended a Latin school during the next few years.  In 1827 he got employment in the office of Mr. Hardiman, Commissioner of the Public Records; and his knowledge of the Irish language, which he had spoken from his infancy, and which he had closely studied from early youth, was then for the first time brought into requisition.  In 1830 he became private tutor in the house of Myles John O'Reilly, Esq., Heath House, Maryborough, where he remained several months.

The following sketch of O'Donovan's early life has been published in the journal of the Royal Historical and Archaeological Association of Ireland, from his own autograph letter to Rev.  Dr. Todd, dated " 49 Bayview Avenue, October 8th, 1843

I was born on the townland of Attatimore (,Ait an tig mor), on the 3rd of August1809.  My father died on the 29th of July, 18I7, when I was about eight years old.  I commenced the study of Latin and Irish when I was about nine years of age, and made considerable progress, though I was exceedingly delicate.  I transcribed Irish pretty well in-1819. Early in I821 I was sent to school to Waterford, by my brother, who had a farm of forty acres in the county of Kilkenny, within four miles of Waterford; and I learned Arithmetic, English Grammar, and Book-Keeping.
" On the 19th of November, 1823, 1 came to Dublin, where my brother had removed, having given up his farm, the lease having expired, and gotten a situation in a merchant's establishment ; and he sent me to a Latin school, till the year 1827.  In that year I became acquainted with Mr. Hardiman, the author of the history of Galway, who was at the time Commissioner of the Public Records; and I remained with him till March, 1830, during which time I copied Peter Connell's Irish Dictionary, which you saw in the British Museum, and other manuscripts, besides doing other business in his office.
" At this time my health got exceedingly bad, and I was invited by my friend, Myles John O'Reilly, Esq., of the Heath House, in the Queen's County, to spend some months with him in the country, to see what effect change of air would have on my constitution.  I spent several months with him, and improved wonderfully in my health, and during my stay with him I translated the
Book of Fenagh, and some extracts from the Annals of the Four Mastersrelating to the O'Reillys ; which was the first thing that induced me to study the Irish Annals.  During my stay at the Heath House I had a great opportunity of studying, and I read the works of Ussher, Ware, and Colgan ; and hearing- of the death of Edward O'Reilly, the author of the Irish Dictionary, I applied to Captain Larcom, then Lieutenant Larcorn, for employment.  I had known Mr. Larcom since the year 1828, when I taught him some lessons in Irish, and he wrote to me immediately, offering me a situation at a very small stipend, of which I accepted after some hesitation, though against the wish of my friend, Mvies O'Reilly, who said it would end in nothing
After my return to Dublin, I received a letter from Mr. Hardiman -asking 'was it a fact that I had given up my idea of going to Maynooth' ? (I have his letter and memoranda of every other fact I mention) ; and I replied stating that I would take some time to consider it.  But I. did not enter Maynooth ever since; and you know the rest of my history as well as any one, ever since.
" Such is the history of mv
bit of learning, to which my friend, Owen Connellan, alludes; and to such did Sir Gay allude when he called me a Philomath, which is, as you know, a contemptible name for a country schoolmaster.  But I will let them pull away as they like, and will continue my acquisition of a bit o' learning as long as my mind is capable of acquiring any.

Your obliged servant,
J. O' Donovan.