anglesey (together with holy island) is one of the 13 historic counties of wales. in medieval times, before the conquest of wales in 1283, "môn" often had periods of temporary independence, as it was frequently bequeathed to the heirs of kings as a sub-kingdom of gwynedd. the last times this occurred were a few years after 1171, following the death of owain gwynedd, when the island was inherited by rhodri ab owain gwynedd, and between 1246 and c. 1255, when it was granted to owain goch as his share of the kingdom. after the conquest of wales by edward i, anglesey was created a county under the terms of the statute of rhuddlan of 1284. prior to this it had been divided into the "cantrefi" of aberffraw, rhosyr and cemaes.