Led by veterans of the Irish Rebellion of 1798, the poorly armed insurgents confronted the colonial forces of Australia on 5 March 1804 at Rouse Hill.

The mostly Irish rebels, having gathered reinforcements, were pursued by colonial forces under George Johnston until they were caught on Rouse Hill on 5 March 1804.

[2][3] Early in 1804, after news arrived of Robert Emmet's attempted rising in Dublin the previous July, a similar conspiracy formed.

[5][6] At 8 o'clock on the evening of 4 March 1804, John Cavenah set fire to his hut at Castle Hill as the signal for the rebellion to begin.

[9] Their move had been informed by the intelligence gathered a year previously, when 12 convicts escaped from Castle Hill, seeking out friends and sympathisers in the surrounding districts.

[12] One hundred and forty men from HMS Calcutta, as well as the Sydney Loyal Association militia, took over guard duties, and a New South Wales Corps contingent of 56 personnel, including Lieutenant William Davies[13] and Quartermaster Sergeant Thomas Laycock, were dispatched to march through the night to bolster the garrison at Parramatta.

[14] Johnston arrived at Government House in Parramatta about four hours later, not long after King had declared martial law under the Mansfield doctrine of posse comitatus.

[20] Meanwhile, the rebels at Constitution Hill (Toongabbie) were having difficulty co-ordinating their force because several parties, including one of around 70 men under Samuel Humes, had lost their way in the night.

Cunningham and Johnston began drilling their men,[21] while a party unsuccessfully tried to enter Parramatta,[22] where they were to set fire to a building to signal other conspirators to begin converging on Constitution Hill.

[24] The commandant at Parramatta, Captain Edward Abbott, who had warning of the rebellion as it was happening, commenced defensive measures and sent a message to the governor in Sydney.

[1] While at Constitution Hill during the short period of the rebellion, Cunningham was elected "King of the Australian Empire", and his followers declared the area "New Ireland".

A small party under a corporal was sent to outflank that position, while an assault force of around a dozen men advanced on the summit, only to find it abandoned, with the rebels having moved off towards the Hawkesbury, about 17 miles (27 km) away.

Demanding their surrender, he received the response "Death or Liberty" from Cunningham,[35] to which some were reported to have added "and a ship to take us home",[36] although that exchange was only once recorded, some time later, by Suttor.

On being given the order to engage, Quartermaster Sergeant Thomas Laycock directed more than fifteen minutes of musket fire at the rebel lines and then charged, cutting Cunningham down with his cutlass.

[39] Several convicts were captured and an unknown number killed in the ensuing pursuit of the rebels, which continued until late in the night, with newly arrived soldiers from Sydney joining in the search.

On Wednesday, 7 March, Governor King announced that those who surrendered before 10 March would receive leniency and, following that, large parties who lost their way in the night turned themselves in under the amnesty, or made their way back to Castle Hill, where a large party of about 70, led by Samuel Humes, was captured by a detachment of the Loyal Parramatta Association.

[41] Of the remaining rebels (approximately 150), some were put on good behaviour orders, in default being sent to Norfolk Island, while the majority were pardoned and allowed to return to their places of employment, it having been adjudged that they were coerced into the uprising.

[45][46] Cunningham, badly wounded but still alive, was court-martialled under the martial law decree, and hanged at the Commissariat Store at Windsor, which he had bragged he would burn down.

"The Government Farm at Castle Hill", a plot of land around 60 hectares (150 acres), was added in March 1986 to the now defunct Register of the National Estate, as a special place of international and Australian significance.