Cormac's army travelled from Tara to Clonard and on this first night on the march southwards, they made camp at Clonard. (Comar na gCuan/Comar Cluana hIoraird)

Cith Rua meets Fios Mac Athfhis, the Chief Druid of Leinster.

That night, Cith Rua, one of Cormac’s old druids, left the camp and went towards the south west until he met a stream. On the other side of the stream he saw Fios Mac Athfhis from Leinster, the chief druid of the area.

The Druids spoke about the march. Both agreed that Cormac would not be successful in his attempts to get tribute from the men of Munster and compensation for the death of his father, and that Cormac’s people would suffer greatly as a result.
They were overheard by servants who reported the conversation to Cormac.

Cormac ordered that his Druid, Cith Rua, be killed. This was revealed to Cith Rua and he returned to camp disguised.

The army followed the Leinster Druid who had headed in a south wards direction, but he blew a magic breath on them. He made everyone in the army appear to look like himself, the grey-haired Leinster Druid. The men turned and tried to wound and kill each other.

Cormac called on his fairy druids for help and they blew a magic breath on the army and the men returned to their own form.

CLONARD ABBEY
This was an early medieval monastery situated on the River Boyne, just beside the traditional boundary line of the northern and southern halves of Ireland, in Co. Meath. Very little remains of the site today. From the air, the outlines of some wall boundaries and other earthworks are visible.
The ancient name for Clonard was Ross Finnchuil, also known as Cluain Ioraird/Cluain Eraird, the meadow of Ioraird.

The Monastery of Clonard was made famous by St Finian in the 6th century. From the Monastery, many men travelled to Britain and Europe, forging links between the Continent and Clonard.

Leinster Bridge, formerly opened in 1831 replacing a much earlier bridge of 9 arches, which spanned the river Boyne.
This bridge has four arches and forms a boundary line between Meath and Kildare on the N4 to the west. Originally here was a ford on the river at this point, before the time of St Finian, that could have been used by Cormac and his army.