According to legend, Sunniva was the heir of an Irish kingdom, but had to flee when a heathen king, who wanted to marry her, invaded. At the Norwegian island of Selja, in the present-day municipality of Selje, she and her followers took refuge in a cave. The locals suspected the foreigners of stealing their sheep, and the ruler Håkon Jarl was sent for. Sunniva and her followers prayed to God that they should not fall into the hands of the heathens, upon which rocks fell down blocking the entrance to the cave.
Sunniva and the others died in the cave, but in the years to come miracles were reported on the island. When the Christian king Olaf Tryggvason excavated the cave in 996, the body of Sunniva was found intact. Later a Benedictine monastery, Selje Abbey, was built on the site, the ruins of which can still be seen.
During the fires in Bergen of 1170/71 and of 1198 the relics of Sunniva were taken from the cathedral and set down at Sandbru. This reportedly halted the advance of the fire and was hailed as a miracle.
The relics appear to have been lost in or around 1536, as a consequence of the Reformation.
Around 1170 the story of Sunniva was written down in a Latin hagiographic work titled Acta sanctorum in Selio.
Runar Calender Seljumannamesse.
Images of St. Sunniva St. Sunniva and St Olav at Nidaros, Trondheim, Norway.
Seljumannamesse, Seljemannamesse, festum Sunnive virginis eller Sankt Sunnivas dag feires til minne om St. Sunniva som etter sagnet omkom i en hule sammen med sine ledsagere, Selje-mennene, på Selje i Nordfjord. Minnedagen er 8. juli og primstavsmerket er en krone (Sunniva var kongedatter), trefork, berg eller hule (der de led martyrdøden).
Dagen er på Østlandet også kjent som Knutsok eller Knut med ljåen (egentlig 10. juli), Kjell fut og tredjevaka (Østlandet). På Vestlandet hadde de en merkedag til, 31. august, etter dagen i 1170 da Sunnivas skrin ble flyttet fra Selje til Bergen. Sunniva er Bergens skytshelgen.