Born about 580, the son of
Bledric ap Custennin, Clemen ruled after his father was killed by King
Æthelfrith of
Northumbria at the Battle of Bangor-is-Coed (
Bangor-on-Dee,
Powys Fadog) in about 613. He married the daughter of Guitoli ap Urbgen, who was possibly a great-grandson of the late king
Gerren Llyngesic, and they had one known son,
Petroc Baladrddellt (“Splintered Spear”) - although, according to the Welsh
Bonedd y Saint (Genealogies of the Saints), Clemen was the father of
St Petroc, other authorities state that this saint lived around a century earlier, the princely son of King
Glywys of Glywysing, making it likely Clemen was actually the father of Petroc
Baladrddellt. Some authors have Tewdwr (or Teudu) son of Peredur ruling as king in the
fl. 620s, descended from a different line of Dumnonian kings from Gerren ''Llyngesic's'' son
Cado ap Gerren. This is as given in the
Jesus College, Oxford, MS 20, although this line ends with a Judhael as Tewdwr's grandson, almost certainly
Judicael,
High King of the
Bretons, and king of
Domnonia in
Brittany. ==Battle of Beandun==