13th century, Old Norse.
Ex(change) of identityagain and again
Birds and animals again snd again
Disguise again and again
The swan is Lara, the mistress of one of the opposing warriors who has turned herself into a bird.
Hromund Gripsson has dreamed badly and has severe misgivings about taking part in this particular battle. But King Olaf’s sister has given him a magic garter to wear around his wrist and so he agrees to help her brother. He has already recovered a ring from the barrow of a warrior king of Gaul.
The day of the battle arrives and a swan can be seen flying over the ice of the battlefield. The swan is Lara, the mistress of one of the opposing warriors who has turned herself into a bird, recalling the swan-maidens of Germanic mythology who can take the form of either a swan or a woman. By the use of her witchcraft, and by some astute aerial reconnaissance, this swan is playing an active and indeed a pivotal role in the battle.
Story fragment recounted from: the medieval Icelandic saga of Hromund Gripsson, translated by Gavin Chappell, chapters 6–7.
Icelandic saga – Wikipedia
Legendary sagas – Wikipedia
Hrómundar saga Gripssonar – Wikipedia
The Saga of Hromund Gripsson – translated by Gavin Chappell: New Northvegr Center