A secret tunnel has been uncovered beneath Carrickfergus Castle.
Archaeologists carrying out a major dig at Ireland's best preserved Anglo-Norman Castle were surprised to find parts of a 18th Century tunnel extending into the area where the medieval Great Hall once stood.
Although these Victorian features have disturbed earlier deposits, they are also allowing archaeologists to dig deeper into the site and uncover substantial remains of what appear to be medieval walls, according to Environment Minister Mark H Durkan.
The minister has now announced that the excavations at Carrickfergus Castle will be extended.
Archaeologists have completed three weeks of exploratory excavations as part of the ongoing work by the Department of the Environment to uncover more of the castle's history and to inform future development of the castle to enhance the visitor's experience.
Mr Durkan said: "The discoveries that the archaeologists have already made at the castle are very impressive and further reinforce my belief in the importance of using archaeology excavations to inform our rich heritage history."
The polygonal inner ward on the tip of the rock is the earliest of the upstanding remains of Carrickfergus Castle that can be seen today. Begun in 1178, it was built in one programme with the great keep.
The middle ward was added between 1217 and 1222, with a postern gate to the sea and the east tower with its cross bow loops at near water level. The outer ward and gatehouse were probably built between 1226 and 1242, taking in the full extent of the rocky promontory.
The gatehouse, traditionally the residence of the constable of the castle, includes on the east side, a chapel, and in the centre, over the gate, the windlass for a portcullis.
Later changes were mainly concerned with the provision for guns and the castle's use as an ordnance depot. Cannon from the 18th and 19th centuries are on show.
The results of the new digs will help guide how the areas are presented to the public and how these areas can be used in the future. Although the excavations will be fenced off for safety purposes, visitors to Carrickfergus Castle will still be able to view the excavations as they take place and see what the archaeologists are uncovering.
Sited on a rocky promontory to command Belfast Lough, Carrickfergus Castle was begun by John De Courcy soon after his 1177 invasion of Ulster. Its long history includes sieges by King John in 1210 and Edward Bruce in 1315, its capture by Schomberg for William III in 1689, and capture by the French under Thurot in 1760. The castle was used by the army until 1928, and housed air-raid shelters during WWII.