Reliability of narrator in Cardenio and Celinde
The unreliable narrator has drawn a fair amount of attention and become increasingly popular over the last few decades.
One of the earliest experimenters here was Faulkner in The Storm and the Fury, where the narrator is closely associated with the handicapped son Benjy. An even earlier case can be found in Henry James's The Bostonians when the indirect discourse attributed to certain characters allows them to usurp and relativize the narration temporarily. Perhaps the earliest example, not due to linguistic aspects, but rather pure logic, is the narrator in Cervante's Don Quixote. His stories are in part so absurd that it is impossible to take his account completely seriously.
The German baroque dramatist and poet Andreas Gryphius seems to have been another writer interested in unreliability. In the first act of his play Cardenio and Celinde, an intruder enters the maiden Olympia's room at night. The eponymous protagonist Cardenio is telling this story to his friend Pamphilius. He relates that ultimately the act was ascribed to himself, although he explains various reasons why it was impossible for him to do so. One is:
Nicht möglich / daß durch List ich heimlich eingekehrt / (It was not possible for me to enter secretly /)
In ein verwahrtes Hauß das allerseits beschlossen: (A house safeguarded well and on all sides locked tight:)
Wenn schon bey später Nacht die Riegel vogeschossen! (And not to mention night with sliding bars in place!)
However, Cardenio's logic does not make sense. First of all, somebody, even if not himself, was able to enter the house and then escape. But later in the play, Cardenio explicitly shows how unreliable his account is when he admits to bribing a maid in a different situation in order to gain access to Olympia after her marriage:
Ich dacht auff neue Stück: Und als er einst verreiset; (I hatched the next idea: And when he took a journey;)
Hatt ein erkauffte Magd mich in sein Hauß geweiset / (A maid I bribed discreet snuck me into his house)
Gryphius had a moral agenda in his work. Among others, he wanted to show the danger of valuing life on earth over life after death. Worldly passions such as ambition, love, etc. destroy various characters in Cardenio and Celinde, while those who renounce them and accept god's fate enjoy peace of mind. The unreliable narration may be reflective of Cardenio's unsettled state at the time of its narration. And indeed Cardenio's statements in his final confession to Olympia, Lysander and Celinde do not conflict with anything we now from the preceding narrative.
Gryphius, Andreas. Cardenio and Celinde: Dual Language Version. Trans. Henry Whittlesey. New York: Perypatetik Media LLC. 2014