Cormac Mac Airt, High King of Ireland, collected an army from three provinces of Ireland and prepared to invade Munster, to collect tribute and taxes by force that he believed were owed to him.

The High King of Ireland was paid tribute or taxes by the Kings of Munster, Leinster, Connacht and Ulster. They in turn collected tribute from lesser kings.

Cormac, the High King, had his own personal army to protect him (The Fianna led by Fionn Mac Cumhaill) but he did not command an army of Ireland. In times of war he called for assistance from the four provincial kings.

War usually took place in Summertime, after the crops were planted and before the harvest. The land in winter could be wet and muddy, making the roads impassable.
War was often fought by single combat between the champion warriors from both sides.

Preparing for the expedition to Munster, he called his druids to examine the omens.
He had five chief druids, Ceathach, Cith Mór, Céacht, Crotha, Cith Rua.
They examined the omens and told Cormac that the invasion of Munster would be a disaster for him.
Cormac was warned by the Druids that his claims were unjust and that the army would be slaughtered. He ignored all advice.

The fairy queen Báirinn Bhláith Bhairche, promised to give him five fairy druids to help in his expedition to Munster, Colpa and Lorga, Eirge, Eang and Eangain.

Cormac was delighted and set out on his expedition.

Monday morning, Cormac and his warriors leave Tara and travel to Clonard. They set up camp outside Clonard.

BACKGROUND TO THE STORY OF THE SIEGE

It had been prophetised by Aonghus that a disastrous cattle disease would occur during the reign of Cormac Mac Airt.

The year of the Cattle disease Cormac collected all his taxes and tributes due from the five provinces of Ireland. This amounted to almost 900 cows. He distributed the tribute generously.
When his own herds died from the disease, he had no provisions for his own people. Cormac would have no revenue until the following year. It would be an unfit king who could not provide hospitality for his people.

Cormac decided to ask the men of Munster for more tribute and taxes. Fiachra at Cnoc Rafann, close to Cahir and the men of Munster assembled and decided they would not pay the tribute.

They knew that Cormac would not accept this offer and they prepared for Cormac’s army to  invade Munster.
Fiachra called on the fighting men of Munster to gather together at Ceann Chláire/ Ceann Abhrat / Sliabh Riabhach /Glenbrohane mountain, for the defence of Munster.

THE HILL OF TARA

Hill (507 feet) in Co. Meath, 6 miles SE of Navan, residence of the High Kings of Ireland
Temair, Teamhair, Temuir
Other names are Cathair Crofhind, Druim Léith, and Fordruim.

According to the Lebor Gabála (The Book of Invasions), the Milesians named the site Temair after Éremón's queen, Téa.

Tara is one of the best known sites in the world and its name is evocative of the Celtic past. On a grey morning in early September with the mounds of Tara shrouded in fog, it is easy to imagine the warriors of Cormac Mac Airt training in the surrounding fields, as athletes trained and prepared on Olympus in Ancient Greece. The glory of Tara is that it is saturated with the past, whether reality or fiction.

The most important mythical king of Tara is Cormac mac Airt.
There are over thirty visible monuments on the Hill of Tara relating to burial and ritual, spanning 4000 years, from 3500BC to the 6-7th Century AD
Tara was an important centre of religious ceremony.
It had been a burial site as early as the second millennium BC.
Tara was the supposedly the seat of the High Kings of Ireland.
Later ‘king of Tara’ was an honorary title for a ruler whose seat was often far distant.
The Uí Néill referred to their kings as ‘kings of Tara’.
Feis Temrach was celebrated on the Hill of Tara

Some features of the Tara site include:

Banqueting Hall’ : Rectangular earthwork, 750 by 90 feet
Cormac's House : Small earthwork enclosed by the Fort/Rath of Kings, at the centre stands the Lia Fáil
Fort/Rath of the Kings : Large, oval hill-fort, 950 by 800 feet, which nearly encircles three other earthworks (Cormac's House, the Mound of Hostages, the Royal Seat) and the Lia Fáil.
Rath of the Synods. : Earth-work excavations showed timber palisades from the 1st and 3rd centuries AD. In the late 19th century British Israelites excavated portions of the earthworks looking for the Ark of the Covenant.
Lia Fáil (stone of destiny) : Twelve-foot erect pillar-stone, 6 feet above ground, made of granular limestone, not quarried in the district. Found lying horizontally near the Mound of Hostages.
Royal Seat : Small earthworks adjacent to Cormac's House

TARA OF THE KINGS : Poem by Cathal O’Byrne

Department of the Environment - National Monuments - Hill of Tara

Heritage Ireland Information on the Hill of Tara

Meath Tourism Information on the Hill of Tara

National Museum Exhibition-Rites of Passage at Tara