Apart from the legend of the Wandering Jew, are there any other in-period stories of people who do not grow old?
The Seven Sleepers of Ephesus could be interpreted as having the Unaging virtue while they slept, but lost it after they left the cave.
This question relates to one of the troupe's Companions, a girl who has been 9 years old for the last 20 years.
The background is that after her father dies, the mother turned to the oldest profession to make ends meet, and was hauled before the ecclesiastical court for moral turpitude (to paraphrase). The Bishop who had chosen to oversee the proceedings, after checking the girl was born into proper wedlock and otherwise pious, Blessed/Cursed her that she remain always as innocent as she was and never suffer the temptations of the flesh (paraphrased as best I remember).
Presumably this Unaging is Divine in origin. We have heard that the Bishop in question is old and dying. Would you expect that the Unaging virtue continue after the Bishop's death?
Just arresting the growing up of a child is a most dubious 'miracle' even for medieval legends. What does the bishop's successor in office think about the likely famous freak his predecessor left in the world? Does he see a need to intervene?
An interesting story could evolve from the still juvenile girl being present at the wonder-working bishop's death bed.
unaging as written doesn't necessarily extend lifespan, just prevents one from getting old. Dick Clark is a modern and very well documented version of this, though probably not quite to the level described in Ars Magica- certainly he did not seem to age within the typical lifespan of a medieval person.
Anyone whose apparent age is much younger than expected could qualify for Unaging or Faerie Blood - therefore Eleanor of Aquitaine (a striking beauty for many years) might appear blessed with Unaging for many years, or may have had a strong magical or faerie lineage (or been a Hermetic maga who didn't get a longevity ritual until her mid 40s as John wasn't born until 1166).
This Companion character is a Failed Apprentice, who sticks around Magi because she has a craving for Magic. I think she had Magic Addiction during Apprenticeship.
From what I recall of the character description, within a year a Magus discovered she was Gentle Gifted and apprenticed her.
After a couple of years, realised she wasn't getting older. Tested her to destruction. Trying to get her unaging essence for an LP? Girl kept Unaging, but lost her Gift.
However, back to the original question.
Our troupe's reasoning went - a properly consecrated Bishop is granted a Divine Might. Perhaps he accidentally tapped into it to Bless with Unaging. Is his Divine Might sustaining the Virtue? What happens to his Divine Might when he dies?
Nothing there for simple bishops - and no Divine Might even for the Pope.
Do you go for bishops of legendary power - and verrry little control of it - in your saga? Anyway you have highly saga-specific rulings and results here.