"Na Connerys"
The Connerys of the songs were three brothers - Patrick, Seán, and Séamus from County Waterford whose family had once been prosperous but by 1829 were reduced to a share of a small hill farm, from which they were later evicted. There are three songs which celebrate the brother's resistance to the power of the hated land agents, and curse the informers who betrayed them to the authorities. The Connery brothers became heroic symbols of resistance in pre-Famine Ireland, and the songs about them reflect their status as upholding the rights of the small farmers and tenants against the land agents, police, and the whole system of 'justice' which deprived them of their own land.
The brothers, in various combinations, were involved in disputes with land agents and lesser officials, and in some factional fights, a gun-battle with police; they were tried for various offences, including murder, and on one occasion acquitted when a crown witness 'forgot' his testimony. The brothers escaped from jail more than once, but were betrayed and recaptured.The man who betrayed them was the man who had seduced their younger sister. Their trials were well-attended and nearly led to riots, and in the unsettled state the huge swell of support for their case could have led to some kind of rural revolt.
The 'facts' of the story are inevitably confusing so perhaps it is better to follow John Ford here:- "When the facts become legend, print the legend."

For more information see the book by Brendan Kiely 'The Connerys' - The Making of a Waterford Legend' (Dungarvan, 1989)