Líon alt a bhfuil an ghné seo luaite iontu: 2
Deir James Maher (Romantic Slievenamon..., 1954): ‘The “onlie begetter” of Knocknagow was the author’s kinsman, Colonel John O’Mahony, who suggested to Charles that he should write something for an American magazine called The Emerald ...’
A token of Cavanagh’s affection for O’Mahony, and of his loyalty to him, can be seen in Cavanagh’s participation in a fund-raising committee and circulating a letter, unknown to the Colonel, in which he explained O’Mahony’s difficulties with the publisher of his translation of Forus Feasa ar Éirinn and sought donations to help O’Mahony settle a debt whereby he would become sole owner of the plates of that book.’ Meastar gur luigh sé isteach ar an iriseoireacht in 1857 nuair a bhunaigh Ó Mathúna agus Doheny an iris The Phoenix ach nach raibh sé ach mar shlí bheatha pháirtaimseartha aige gur bunaíodh an iris The Emerald in 1868