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The Nunnery

Also known as, or recorded in historical documents as;
Les Murs de Bas; Chateau de Longis; Lower Fort; Castrum Longini; Lower Fort

On the Isle of Alderney.

Latitude 49.72100° Longitude -2.17600°

The Nunnery has been described as a certain Fortified Manor House, and also as a probable Artillery Fort.

There are major building remains.


The Roman fort, known locally as the 'Nunnery', is found at the bottom of Bluestone Hill. This site epitomises the way that strategically important positions on Alderney have been adopted and reused during each wave of fortifications the island.
Located at the western end of Longis beach the small fort, once known as Les Murs de Bas, or Lower Fort, and known today as the ‘Nunnery’, is, after recent archaeological investigations, now considered to be almost certainly Roman in origin. Its shape has striking resemblances to the five Roman so-called signal-station forts on the Yorkshire coast. This fort is the first evidence of military construction in Alderney. In addition the fort was used during the French Revolutionary and Napoleonic Wars, as a hospital and married quarters in Victorian times and was converted to a German strong point in the Second World War. (Alderney The Channel Island website)

First recorded as a military blockhouse in the 14th century, by the late 16th century it had become home to the Chamberlain family, governors of Alderney. In 1739, when English military surveyors planned it, the building was ruinous, but was refortified with cannons, before becoming a barracks and then a farm. (Monaghan 2011)

Aldernay was surveyed with consideration for a defence in 1547 and work was in progress by 1549. By 1553 £9210 had been spent but in 1554 Queen Mary's Council order the work stopped, the ordnance to be removed and the buildings to be 'rased and defaced'. Although dismantled rather than demolished, the forts were never rehabilitated, and for the rest of the sixteenth century Alderney remained without effective defences. The Tudor forts appear to have been those known as Essex Fort, overlooking the harbour in Longis Bay, and the 'Chateau de Longis', or 'the Nunnery' (as it was later called), on the shore of the same bay. The latter incorporated the shell of an earlier fortification possibly of Roman date, and was converted into a dwelling in 1584-6. The former was never finished and was partly demolished to make way for a Victorian fort in the 1840s. (HKW)

Comments (by Philip Davis)

The site has, quite understandably, aroused considerable interest amongst students of Roman studies. The medieval history of the site is mainly overlooked. The Roman signal station would have had a tall central tower and it may be that this was 'the highest tower' on which John Sperston was to 'display the arms of England, 'to remind and inform all who pass by that the island is held of the crown of England fovever'.' (Thornton) but this tower has been lost at a later date (alternatively the 'highest tower' may have been a watch tower on the hill above the bay later to be the site of Les Murs de Haut). Certainly Alderney was vulnerable to pirate raids (some of considerable size; 2000 Bretons were reportedly involved in an early C15 assault) and the need for defence, combined with a degree of poverty, may well explain the outstanding preservation of the Roman fort where the Roman work was always well maintained but there was never enough money to alter or upgrade the fort. However there was money available in the 1550s and it may be the central pharos of the Roman signal station was removed at that time although it seems likely the bulk of that money went on building the upper fort of Les Murs de Haut. Later fortifications of the island based on long range artillery used high ground and thus also tended to avoid altering the Nunnery.
Leland marks, on a sketch map of the Channel Islands, a castrum Longini on the east end of Alderney. This may represent this building, apparently called Chateau de Longis' just a few years later but can not represent Les Murs de Haut which was begun in 1546, after Leland's time, and which is now consumed within Essex Castle.
It should also be noted that while the modern landing place of Alderney is Braye Bay on the north side of the island in medieval time Longis Bay was the only safe landing place and the rest of the island is protected by steep cliffs. It is not known if the Roman fort continued to be used as a lighthouse after the end of the Roman period but Alderney is not well supplied with wood and the shortage of fuel probably means this was unlikely.
A very damaged role of the assizes held on the islands in 1309 may mention a castrum in Alderney. If this was a castle on the island then the Nunnery may be its location. N.B. The medieval use of the term castrum was nuanced and varied, particularly when used by members of a small isolated island community, and need not necessarily mean a fortified place but could refer to the local manorial court.
In practice the main function of the building must have been as a base for the collection of landing fees and other tolls and some individuals must have been employed to take these but are likely also to have been armed, However the island was never able to effectively defend itself and survived attack mainly from being too poor and insignificant to be worth the expense of raiding.
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This record last updated on Tuesday, April 18, 2017