King Nunna, also known as Noðhelm and Nothhelm ruled Sussex from 688 until his death in 720. He is described in the Anglo-Saxon Chronicle as kinsman of King Ine, although it is not clear if this is by blood or by marriage.
King Nunna accepted the over-kingship of Ine and does appear to have enjoyed a good relationship with him. Nunna signed a number of Sussex charters as king, rather than Ine. Both were recently converted to Christianity. The majority of Sussex was converted to Christianity by Bishop Wilfred in 672.
In 692 Nunna granted additional lands to the abbey of Selsea and to his sister Noðgyð to enable her to construct a monastery and later become a nun. In 705 the Kingdom of Sussex was stable enough for the church to reestablish the see of Selsea.
Nunna fought with Ine against Geraint, King of the Britons, in the year 710. This battle took place near the borders of Dumnonia (modern day Devon and Cornwall), the last remaining Briton stronghold on the south of Britain. Geraint died in the battle, allowing Ine to expand the boundaries of Wessex.
After Nunna’s death, the rebel Eadbert sought refuge in Sussex in 722 after his defeat at Taunton by Queen Æthelburg (Ine’s wife). He was perhaps hoping to set himself up as King of Sussex, but Ine pursued, defeated and killed Eadbert in the subsequent battle.