A medieval castle, believed to be one of the first built in Ulster, has been uncovered during an excavation at a former military base in Co Tyrone.
Structures believed to be the remains of an early 14th century castle built by Irish chieftain Domnall O'Neill have been found by archaeologists in Dungannon town centre.
However, plans for redevelopment of the land mean the extent of the first permanent headquarters of one of Ireland's most powerful ancient clans might never be fully known.
The site at Castle Hill is currently being vacated by the PSNI, which had accommodation barracks there. Previously it had been a Territorial Army base, before being taken over at the start of the Troubles in 1969 by the British army.
The last soldiers left the base in 1987 when the then RUC leased the premises owned by the local Orange Order.
It is understood that Dungannon and South Tyrone Council are currently in negotiations to purchase or lease the land from the Order for a town park.
Castle Hill had long been pinpointed by historians as the location of the O'Neill stronghold. The clan, named after Niall, King of Ireland, who was killed in battle with Norsemen around 919AD, were a phenomenal force in medieval Ireland, figuring prominently among great figures in Irish history.
The O'Neills (or Ui Neill) were the chief family of the Cinel Eoghan – their territory of Tir Eoghan, from which modern day Tyrone is derived, encompassing not only that county but much of Derry and part of Donegal.
Contemporary references to the castle are few, but a number have been uncovered in ancient annals relating to the area.
Dr Tom McNeill of the medieval history department at Queen's University of Belfast, visited the site during part of the excavation.
"There are a few one-line references in fifteenth century documents. You would get one and then there would be another one 20 years later," he said.
"Put together they indicate that there was an O'Neill castle in that area."
Before the police finally leave the premises they have been carrying out construction work to secure a radio communications mast used for 999 emergency calls.
During work by contractors, a two-metre long and 1.2m high stretch of wall was uncovered.
Given the level of historical interest in the site, Northern Archaeological Consultancy Ltd was drafted in to examine the areas which would be affected by the building work.
Site director Robert Chapple said the team of archaeologists had recovered 4,000 artefacts dating from the late medieval to the post-medieval periods.
The medieval features include a defensive wall which, although very heavily damaged, appears to bear "significant resemblance to some of the ancillary defences shown on the well-known Bartlett map of 1602".
The original castle is believed to have been some sort of 'tower house' type structure, built in the time of Domnall O'Neill.
Further forensic examination on the recovered items is still to take place before they can be definitively dated.
However, Mr Chapple is confident the find will yield valuable new evidence about the original castle and subsequent structures built on the site.
At least two castles were built by the O'Neills alone.
The site was abandoned by the O'Neills following the Flight of the Earls in 1607, when Hugh O'Neill left Ireland for voluntary exile in Italy after being stripped of his kingship by the English Crown.
He had previously been pardoned by Queen Elizabeth I after a rebellion against her rule during which time he used lead from the roof of his new castle at Dungannon.
"The tower house was destroyed prior to 1602 and the destroyed remains were record- ed on a map by a man called Bartlett," he said.
"Following the Flight of the Earls the site was taken over by Sir Arthur Chichester-Clark who built a castle in the seventeenth century.
"That castle lasted until the 1630s before it was destroyed and then finally in the 1780s when Knox-Hannyngton built a gentleman's residence with four corner towers.
"We have been finding stuff from the O'Neill castle, pieces that may well be from Sir Arthur Chichester-Clark's castle and we have also found pieces which can be identified as part of a fifteenth century tower house."
The excavated areas of the site have since been concreted over – a measure which will preserve remains, but which prevents any further excavation. There are currently no plans to investigate the site any further, leaving a potential archaeological goldmine unexplored for the foreseeable future.
Dr McNeill said the ruin holds valuable information about life in medieval Ireland.
"We need to know what's going on inside the walls of the castle, there should be a more substantial excavation of a wider area so we can see what is happening in terms of internal buildings," he said.
"In other Gaelic areas, in Scotland and Wales there were castles being built in the twelfth and thirteenth centuries, continuing through to the seventeenth century.
"In Ireland we don't get that early phase, it only starts in the 14th and 15th centuries."
The building of a castle by a lord in mediaeval times created a trading centre in an area, beginning the transition from a farming society to a market town.
"By fixing a single permanent headquarters in one place it changed the nature of the succession to Irish lordship. Previously any relatives of the former lord had a claim to the throne, now the person who could secure the castle could grab the power," Dr McNeill explained.
"This would be a very important example of how Irish lordship became more settled, more like English lordship. The O'Neills were very major players at this time.
"This is the first time the site has been excavated because the house which was built there was taken over by the army and then the police as a security base which no one could gain access to."
But he said that, while there appeared to be genuine remains there, it was unlikely they would be properly excavated for another generation.
"It is in many ways an opportunity seriously missed to have a look properly at what's there," Dr McNeill said.
