Back in the early 1990s, the archaeologist Neil Johnson directed an excavation of the Llys Rhosyr site in Newborough. This was part of a programme to try and identify locations of the royal llysoedd (courts) of the Welsh princes of Gwynedd.

During the 12th and 13th centuries, the princes of Gwynedd built up a network of royal estates at certain townships within their kingdoms. Gwynedd was divided into administrative areas, called cwmwd/cymydau (commote/s). The main town of each commote was the maerdref and in each maerdref was a llys - a court, or type of estate centre.

These centres would have a big hall, outbuildings associated with running the commote, residences for the princes and their visitors and a community of bond tenants, essentially estate workers and agents of the princes.

All rent and dues owed to the princes from the commote were paid to the estate. As money didn't come into popular use until the late 13th century, people paid their dues in kind with food or services, so it was easier to have many estates local to each area all over the principality.

The princes and their entourage would move from llys to llys to do business, sign charters etc. There were six commotes on Anglesey - Llys Rhosyr was located in the maerdref of Newborough, in the commote of Menai.

In searching for the location of Llys Rhosyr, archaeologists spoke to local people and discovered that there was a field near St Peter's church known as Cae Llys. This site is just on the fringe of modern Newborough, up on the Gallt Bedr ridge. The old Medieval maerdref of Newborough was located around the crossroads to the town, on the road down to Llanddwyn beach.

Excavations uncovered evidence of stonework and foundations beneath a depth of sand blown in from the coast. They identified a number of important structures, surviving at least a foot or two above the foundations under the sand.

You can see part of the perimeter wall of the rectangle enclosing the llys, a hall, a chamber block and two other buildings. Llys Rhosyr is one of the very rare instances of a surviving or identifiable royal llys, outside the large castles.

With the conquest of Gwynedd in 1283, the royal lands of Llywelyn ap Gruffydd (Llewelyn The Last), were forfeited to the English crown. When Edward I built his new castle in Beaumaris, the adjacent maerdref of Llaenfaes, previously a flourishing town, was depopulated. Edward's agents decided instead to create a commercial centre on the land of another commote's centre - Llys Rhosyr.

The present day Newborough still stands on the old pattern of roads and tenancies which Edward I's surveyors laid out in 1300.

Photos of the excavation work.