What the earliest instance of an average human being magically summoned to another world, while being ignorant about the actual summons?
Basically, it's Summon Everyman Hero trope, but restricted to the summoning being the result of an actual summoning spell, and not technology, and unaware that they are being summoned.
The basic description for that trope is:
An average person from our world is brought into another for a wacky adventure.
So I'm asking about
An average person from our world is brought, by magic spell, into another for a wacky adventure.
If the dates for the earliest instance change if depending on if the spell was intended as a summoning spell, and/or if the summoned person was the intended summon, then list those instances too, please.
And so, A Connecticut Yankee in King Arthur's Court, is not a valid answer as the hero was not summoned by a spell, but instead:
Hank Morgan, a resident of Hartford, Connecticut, suffers a blow to the head and inexplicably awakens to find himself in sixth century Britain.
Something like Hiraga Saito from Zero no Tsukaima, or Parson A. Gotti from Erfworld, would fit.
The first touched a magic portal, without knowing it was a magic portal and it whisked him off to a fantasy world.
The second was just suddenly plucked out of his universe while making a half-joking comment about wanting to travel to another world.
Peter Pan's transfer of Wendy into Neverland would not count, as it's physical, and the only magical component is the fairy dust, so I wouldn't call it a summon, but a magically-assisted, mainly voluntary, universal transfer.
A magic spell is defined as a planned process by actors that are known to the readers by the end of the story, that is called 'magic' in-universe, and should be instantaneous, or close to it.