“ID: I09900
Name: *Llywelyn Ap SEISYLLT
Sex: M
Name: Llywelyn Ap SEISYLLT
Birth: ABT 980 in Rhuddlan, Flintshire, Wales
Death: 1023 1
Death: 1021
Occupation: BET 1018 AND 1023 Prince of Gwynedd 1
Note:
Nothing is known about Llywelyn's father Seisyll, who may not have been of royal blood, though Llywelyn's mother Angharad was the daughter of Maredydd ab Owain, who ruled much of both nothern and southern Wales for a period.

Llywelyn won control of Gwynedd in 1018 when he defeated Aeddan ap Blegywryd in battle, killing him and his four sons. He later gained control of Deheubarth, defeating Rhain, an Irish pretender who claimed to be the son of Maredydd ab Owain, at Abergwili in 1022. According to the annals in Brut y Tywysogion, his reign was a period of prosperity, but it was cut short by his premature death in 1023.

His son, Gruffydd ap Llywelyn, though still a youth when his father died, was later able to gain control of almost the whole of Wales.
(From Wikipedia, the free encyclopedia)

LLEWELYN AP SITSYLHT who succeeded Aedan ap Blegorad as Prince of North Wales 1015, he being then Prince of South Wales; slain 1021; first husband of Anghared, daughter and sole heiress of Meredith ap Owen, Prince of North Wales (ped. 156). She married, second, Confyn, Prince of Powys in right of his wife.
(Fenwick Allied Ancestry, page 185)


Father: *Seisyll Ap EDNYWAIN b: ABT 938 in Wales
Mother: *Prawst Verch ELISE b: ABT 940 in Gwynedd, Wales

Marriage 1 *Angharad Verch MAREDYDD b: ABT 982 in Deheubarth, Wales
Children
*Gruffudd ap LLEWELYN b: ABT 1000 in Rhuddlan, Flintshire, Wales

Marriage 2 Ealdgyth of MERCIA

Sources:
Title: 1Wikipedia, the free encyclopedia
”