ancient Mona
County (pop., 2001: 66,828), Wales.
It encompasses Anglesey island, the largest island in England and Wales (276 sq mi [715 sq km]), and Holy Island. Anglesey island is known for its ancient history and its prehistoric and Celtic remains. By 100 BC the Celts had colonized the island, which became a famous Druid centre and later a stronghold of resistance to the Romans. It finally fell to Agricola in AD 78. It was ruled by the princes of Wales in the 7th13th centuries, until it was taken by Edward I . Tourism is now an important part of the county's economy.