The aim of this study is to present the manuscript "Manzum Mektup" written by a poet with the pseudonym "Hâdî”. The manuscript, which is a single copy and author's own handwriting, consists of a prose introduction and a poem written in kasîde verse style. In the introduction, it is mentioned that this letter was presented to "Fuad Pasha" and was written as a nazîre to the poet "Nef'î", who had passed away before. There is no information about this work and its poet, other than the ones given above. Another purpose of this article is to determine the real name of the poet with the pseudonym Hâdî, who is the author of the manuscript, and to answer the question of who Fuad Pasha is, to whom the work is presented. As a result, based on some clues given in the letter about Fuad Pasha's life, it has been determined that the work was written for Keçecizâde Fuad Pasha, one of the great statesmen of the Tanzîmat period, and that Hâdî was a poet named Ali Hâdî, who lived in the same period. In addition, in our study, we focused on manzum mektup in Turkish literature and gave some information about its style, genre, language, expression and style. We also quoted the entire Young Osman Kasîda by Nef'î, which we determined to be the ground poem for the manzum mektup, and we wrote the original text of the letter with the transcription method.