This is the 19066th most frequent Korean word.
아센바흐에게
"To Aschenbach" (a dative form referring to the character in the context).
In this sentence, '아센바흐에게' is used to indicate the recipient of gratitude.
나는 아센바흐에게 고마움을 전했다.
I expressed gratitude to Aschenbach.
Here, '아센바흐에게서' is used to indicate the source of the letter, implying it was sent by Aschenbach.
아센바흐에게서 온 편지를 읽었다.
I read the letter that came from Aschenbach.
In this usage, '아센바흐에게' identifies the person we need to pose the question to.