According to Helen K. Johnson's 'Our Familiar Songs, and Those That Made Them', 1881 (with considerably better notes than in most books of that ilk). The song originally consisted of 3 stanzas written by Henry Bennett and a Mr. Toleken of Cork, in 1814, and they sang alternate lines of it in a mmasquerade. Mr. Toleken slightly later added another stanza, and 2 stanzas are of unknown origin (but are obviously early ones). (Commencement of verses follows; numbers are those in her text)

Joint:
1: Saint Patrick was a gentleman
2: There's not a mile in Ireland's isle
5: The Wicklow hills are very high

Toleken's:
6: Oh! was I but fortunate

Unknown origin:
3: Nine hundred thousand vipers
4: No wonder that those Irish lads