Lieutenant-General Lake proclaimed martial law in Belfast and searched for firearms, making mass arrests and seeing to a number of hangings.  Some United Irishmen like John Hoey and Anthony Marmion were executed. Others like Bartholomew Teeling, John Byre and Patrick Byrne, all from Castletown, and Andrew McCann from Corderry were lucky to escape with their lives. Arthur Marmion's Uncle John Magenis was leader of the United Irishmen escaped after his home was burned with his family inside, his family luckily survived.
Clearly there was much provocation in the area:
Near the town of Newry, on the 23rd of June (St John's eve), a number of people, gathered round a bonfire, were deliberately fired upon by a corps of yeomanry, many of them being killed and many wounded. When some of the more humane magistrates of the county applied to Government for assistance, they received from Mr Trail, secretary to the Duke of Richmond, an answer to this effect: -- That the Government could not accede to their request as any steps taken by them would supersede the exertions of the local magistrates. It is needless to say that no steps were ever taken, and these murderers escaped, at least from human justice. Thus did the Government evince its determination to rule through the Orange magistrates, to the entire exclusion of the Liberal Protestants.
-- Carlow Magazine, date unknown
Other members of the family were deeply involved.
Arthur Marmion's Uncle John Magenis was one of the ringleaders, a role which he paid dearly for.
In many ways the politics of the 1790s, radical, Catholic and Defender, crystallised in the Teeling family. It played a crucial role in co-ordinating the coalition between the Defenders and United Irishmen. The father, Luke, a wealthy linen merchant from Lisburn, near Belfast, acted as a (hardline) United Irish surrogate at the Catholic Convention in 1792. It was he who that year paid for the Address to the Defenders, at Rathfryland and for the insertions of the Meath Catholics meeting called to protest against Fitzwilliam's recall, and his young son Charles  then only 17  acted as secretary. Charles brother-in-law, John Magennis,  Grand Master of the County Down Defenders, represented that county at the Catholic Convention, handled the local Catholic Committee subscription and was in communication with the committee secretary (and United Irishman) Richard McCormick. Although the Defenders have usually been discussed at a general  and nameless  level, attention to detail reveals, at first in Ulster, then radiating outwards, a compact nexus of friends and relatives at the head of the movement. This was a group which was, moreover, deeply involved with the United Irishmen. The Teelings stood at the centre of the nexus and, as prosperous linen merchants, typified it.
Anthony Marmion of Restover, hanged at Downpatrick
We don't know a lot about Anthony Marmion, and that while many got away, he was unlucky enough to get caught and hanged for his being in the wrong place at the wrong time.
The Trial
Anthony Marmion who was executed in Dundalk was from outside Rostrevor in County Down, this is about six miles from Newry and on the other side of the mountains from Lurganconary he is not to be confused with another Anthony Marmion who was based in Dundalk and was a Barrister who was active in the cause of Catholic emancipation.

In Antrim or Down, the United Irish rebellion, with a few expectations would have been supported by a Presbyterian but, in Louth, there was very little chance of support fo the movement.. In a largely Catholic area, a Presbyterian is likely have stood against the United men, fearing Catholic domination of an independent Ireland. Remember that the Catholics were the minority in Northern Ireland.

The local Defenders had been active for some time with their outrages peaking around 1791 and 1792 and causing the authorities to clamp down with 114 people transported to Botany Bay in Australia and 21 sentenced to death. Among them Patrick Marmion, listed as "political prisoner".  This weakened the Defender cause sufficiently that, when the United Irishmen were banned in 1794 and many fled to France. Robert Emmet returned to Ireland to deal with unfisished business in 1803, he was hanged 2 months later.