Arianwen

Arianwen is a Welsh holy woman of the early centuries, one of the daughters of Brychan according to an eleventh-⁠century document called the Cognatio de Brychan. She lived in the sixth century, in the region of Brecon. Gerald of Wales recalled in 1188 the tradition of Brychan's twenty-⁠four daughters, and Arianwen is in his list.

Brychan was a ruler and the father of many saints, from whom the kingdom of Brycheiniog in south-⁠east Wales is named; his day is 5 April and he is known to have married three times. Arianwen married Iorwerth Hirfawd (sometimes "Hirflawdd"), king of Powys. Among her sisters or half-⁠sisters are Rhiangar, Gwladys, Gwawr, Nefydd, Marchell, Meleri, Dwynwen, Tybïe and Tangwystl. The source gives no feast day for her.