He was a strongly religious king and the first openly Christian king of the Picts, founding the churches at Abernathy and Kildare.
He provided refuge to Eanfrith, son of Aethelfrith of Northumbria, in 617.
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Nechtan was perhaps a grandson, rather than son of (U)Erb....from Wikipedia:
Nechtan grandson of Uerb, was king of the Picts from 597 to around 620. It is has been suggested that this Nechtan is the same person as the Neithon who ruled the kingdom of Alt Clut.
According to the Pictish Chronicle, Nechtan reigned for 20 or 21 years. While the death of his predecessor Gartnait is given in 597 by the Annals of Tigernach, the death of Nechtan is not certainly recorded. He may be the Nechtan son of Canu whose death appears in the Annals of Ulster for 621, although this would be difficult to reconcile with the idea that he was Neithon son of Guipno son of Dumnagual Hen of Alt Clut.
It has been suggested that the Canu or Cano referred to in the Annals of Ulster is the Canu Garb named by Senchus fer n-Alban, making this Nechtan the grandson of Gartnait II, who has been suggested as a son of Áedán mac Gabráin of Dál Riata
[Note: This is a chronologically improbable theory as it would make a great-grandson of Áedán a king in the 6th century..Bannerman, pp. 92–94]
It is uncertain whether it is this Nechtan or Nechtan I who should be linked with the foundation of the monastery at Abernethy, but since this Nechtan reigned after the foundation of Iona by Columba, ties with Irish monastic houses are more plausible in his reign. The account of Abernethy's foundation in the Pictish Chronicle, in a version likely compiled by the monks of Abernethy, is as follows, with Nechtan I as the subject:
"So Nectonius the Great, Uuirp's son, the king of all the provinces of the Picts, offered to Saint Brigid, to the day of judgement, Abernethy, with its territories ... Now the cause of the offering was this. Nectonius, living in a life of exile, when his brother Drest expelled him to Ireland, begged Saint Brigid to beseech God for him. And she prayed for him, and said: "If thou reach thy country, the Lord will have pity on thee. Thou shalt possess in peace the kingdom of the Picts."
