Gwenllian

Derived from the Welsh elements gwen meaning "white, blessed" and possibly lliain meaning "flaxen, made of linen" or lliant meaning "flow, flood". This name was used by medieval Welsh royalty, notably by a 12th-century princess of Deheubarth who died in battle with the Normans. It was also borne by the 13th-century daughter of Llywelyn ap Gruffudd, the last prince of Gwynedd.