The remains of a court at Newborough (known as Rhosyr up till the 14th century, and Rhosfair before that) was discovered in the late 1990s.
It was once one of five such courts on Anglesey. In mediaeval times the kings and princes of Wales travelled up and down their kingdoms and they would stay at the Llys (court). From there they would sit in judgement on any local disputes, and oversee the local administration of their lands.
The kingdom of Gwynedd, which had been around since the 5th century, was later to fight fierce battles with the Vikings during the 8th and 9th centuries, and after the Norman conquest of England in 1066, the Normans became a real threat to the Kingdom of Gwynedd. Llywellyn ap Iorwerth (Llywelyn the Great), the prince of Gwynedd is known to have issued a charter from this Llys in 237.
The site is in excellent condition and is well worth a visit by anyone with an interest in Welsh and/or Anglesey history. It is in a field to the left of St Pedr`s church, which undoubtedly would have had some connection to the court. I believe that the site was re-discovered purely because the field in which it lay was always called Cae Llys (Court Field), and this kind of gave the game away I suppose.
There is a beautiful hall in Newborough called the J. Pritchard Jones Memorial Hall. The foundation stone was laid in 1902. The drive into the courtyard to this building is also home to the local war memorial.