According to the History of County Longford (published 1898), in 858 BC an army composed of Lagenians, Connacians, and the southern Hy Nialls, marched to Fiachla, under the conduct of Mael-saghlin, the son of Maelrony, and encamped at Moydumha, in the vicinity of Ardagh.

[2] The ancient name of this parish was Kilmodhain, or Kilmacdhumha, so called from being the kil or cell of St. Modhain, or Modiud the Simple, whose feast is celebrated on 12 February, according to the Lives of the Saints.

A peculiar kind of stone, called puddingstone, is found on the isolated mountain of Slieve Gouldry, on the southern confines of the parish, and there is a quarry of freestone, which was worked for flags.

A comely chieftain's son, named Leath, loved Bri, the beautiful daughter of a powerful chief who lived on this hill, then called Tu Uynahearinaghtrihi.

As history tells, they were first called "Levellers," from the fact of their assembling at night and letting the fences with which the landlords endeavoured to enclose certain commons that had previously belonged to the people.

But the pent-up agony of a long persecuted race having once found vent was not to be easily crushed, and for a period of twenty years the Whiteboys were the only protection the unfortunate Catholics had in their troubles.

These men, most of whom banded together for the one noble object—to relieve their distressed condition—when going to perform any act of violence, blackened their faces and put on a white shirt over their dress as a disguise, from which they were called "Whiteboys."

For many years they, by the very terror of their name, restrained the landlords and agents who were inclined to oppress the people—which was most essential to the very existence of the latter[clarification needed]; and when they were at length condemned by church priests, it was because unscrupulous persons had, by bloody acts, turned the association to their own base purposes.

About the year 1780 there lived in Bawn House a certain Captain Barnes, agent over several estates in the neighbourhood of Moydow, and famed among the people as an uncompromising exterminator of the tenants, whom he ruled with a rod of iron.

While thus engaged, a thundering summons came to the front door, and immediately divining the cause, Barnes and his clerk piled up a lot of furniture on the main stairway, first locking the room in which the money was left.

The summons to open the door not being answered, the men, who were Whiteboys that had previously committed several acts of violence in the neighbourhood, burst it in with a tree log, which they used as a ram, and were about to rush upstairs when Barnes fired down on them.

The rest then ran up and knocked the clerk on the head, leaving him senseless, whilst they entered Barnes' office and abstracted every penny he had received that day.

It is told that one day, during the plantation regime, there came a discharged soldier to the town of Longford, who asked to be shown certain portions of land in Moydow which he was after being granted for his services to the Parliament.

The man that met him was a butler in the local inn in Longford, who was possessed of some money; and he volunteered to show the discharged trooper the lands.

The butler took him at his word, handed him out the money, and got him a horse, and in return received the title-deeds of a property which he converted into the Mount Jessop Estate, being the first of its owners himself.

This priory was founded about the year 1205, by Grormgal O'Quinn, Lord of Rath-cline, and was dedicated to St. Peter; and in 1217, the first abbot of the monastery, Osin by name, died and was interred here.

On the death of Brendan Jifagodaig, Bishop of Ardagh, in 1255, his remains also were interred in this priory, which continued to exist until 1550, when it was suppressed, and the buildings and land, to the value of £2 annually, Irish money, were bestowed on one Nicholas Alymor, an English soldier.

The principal Irish families were : – The Caseys, 12 people; Oormicks and MacCormicks, 19; Donlans, 7; Dooners, 5; Duffs, 6; Farrells, 23; Kennys, 16; Morrows, 7; Powers, 6; Keegans, 7; and M'Evoys, 6.