Hmm…

• General bans on Necromancy at various points preventing those spells from getting into or staying in circulation
• Spells and funeral rights preventing the dead from being conjured up (like the Ansei Wards)
• Not knowing who to call up for a given event/time period (any random farmer probably wouldn’t do, you’d need someone close to or involved in whatever you’re researching), which requires records that have a nasty habit of getting destroyed by the many, many conflicts across Tamriel’s history…

Might also depend on how/where they died? Interference if they were soul trapped or otherwise got sent to one of the Daedric realms (due to vampirism or lycanthropy for example) seems plausible to me. And IIRC for Dunmer ancestral magic the big difference between that and standard necromancy is that the spirit isn’t coerced to come back; maybe most people aren’t interested in leaving their cozy afterlife after they die.

ArchMikem wrote: »

WhiteCoatSyndrome wrote: »

Hmm…

• General bans on Necromancy at various points preventing those spells from getting into or staying in circulation
• Spells and funeral rights preventing the dead from being conjured up (like the Ansei Wards)
• Not knowing who to call up for a given event/time period (any random farmer probably wouldn’t do, you’d need someone close to or involved in whatever you’re researching), which requires records that have a nasty habit of getting destroyed by the many, many conflicts across Tamriel’s history…

Might also depend on how/where they died? Interference if they were soul trapped or otherwise got sent to one of the Daedric realms (due to vampirism or lycanthropy for example) seems plausible to me. And IIRC for Dunmer ancestral magic the big difference between that and standard necromancy is that the spirit isn’t coerced to come back; maybe most people aren’t interested in leaving their cozy afterlife after they die.

I thought about some of your points after posting the OP actually. I think I had forgotten the Summoner needs to have some kind of items or personal knowledge relating to the Soul that's being Summoned, like an Aetherial Phone Call, you need the Soul's number.

Also, they wouldn't be able to verify whether any accounts given were accurate or not.

A couple of examples about this come to mind just from ESO alone. Near the beginning of the Vvardenfell main questline, Vivec asks a young member of the Temple to inquire one of their ancestor spirits about stuff, and while that was more in relation to current events that Vivec had noticed, the principle is the same. It has been years since I did that quest, but I seem to recall that the ancestor spirit in question was quite cryptic with its answers - at the very least, the temple priest who summoned the spirit did not understand them, though a part of that was simply because the questions Vivec wanted to ask were also cryptic by themselves.

Another is the quest tied to Forelhost in The Rift, which I can recall quite well as I always end up doing it whenever I hunt for the Skyshard found there. A group of Worm Cultists had gone to Forelhost seeking the Mask of the Dragon Priest buried there, and were planning in summoning and binding the spirits of the Ancient Nords to learn about its location. They all perished to the cold, sabre cats and draugr, however, but the Vestige ends up summoning one of the Worm Cultist's spirits to question them about their intentions. The ritual makes the spirit compelled to answer their questions, but they are very much not happy about doing so.

So, there's definitely lore precedent for using Necromancy to summon spirits from the past to question them, but I believe the points brought up already give good reasons as to why this isn't exactly a wide-spread method, limited to those who care little for what the dead might think about being forced back (The Worm Cult), cultures where communing with the dead is at least semi-common (Dunmer), and perhaps those who practice "ethical" Necromancy like Vastarie. There's no guarantee that the dead will be truthful with their answers, especially if they are angered by the summoning, and if they are not, the answers they give might be cryptic in nature.