Kafka, one of the 20th century s greatest writers, known for works such as "The Trial" and "The Metamorphosis", wrote the letter to Austrian poet and publisher Albert Ehrenstein, in what is believed to be a response for a request to contribute to literary journal "Die Gefährten".

In the one-page letter in German and signed just "Kafka", the Prague-born novelist says he has not written anything in three years.

It is believed to have been written around April-June 1920 from a sanatorium in Merano in northern Italy, according to auction house Sotheby s. Kafka was diagnosed with tuberculosis in 1917, which he does not discuss in the letter.

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"When worries have penetrated to a certain layer of inner existence, writing and complaining obviously cease, indeed my resistance was not too strong," Kafta wrote, according to a translation.

Sotheby’s is offering the letter in its “Books, Manuscripts and Music from Medieval to Modern” sale, running June 26 — July 11, with a price estimate of 70,000 pounds — 90,000 pounds ($88,445 — $113,715).

“It is a very poignant letter written towards the end of his life, where he expresses his despair at writing again and his feelings of... of writer’s block,” Gabriel Heaton, specialist in books and manuscripts at Sotheby’s, told Reuters.

“He’s physically very, very weak and he’s beginning, however, this very intense correspondence with Milena (Pollakova-Jesenska), this great love of his last years, which would spark renewed creativity. So although he’s here in despair, he’s actually on the verge of one final bout of wonderful, wonderful writing.”

Kafka went on to write The Castle and A Hunger Artist. He died on June 3, 1924, aged 40. Ehrenstein eventually sent the letter to artist Dolly Perutz. It is being sold with the envelope Ehrenstein used.