Masdariyecizāde Hüseyin Efendi, one of the lecturers at Mühendishāne-i Berrī-i Hümāyūn (The Imperial School of Military Engineering), wrote a treatise in h.1238/c.1822 on the ancient problem of trisecting an angle smaller than ninety degrees using Euclidean geometry. This famous problem has its roots in the ancient Greek. The treatise contains an assumed solution to the problem by using tools of Euclidean geometry, a straightedge (an unmarked ruler) and a compass. The proof is recorded under the signatures indicating the approval of the engineering faculty. The available academic literature on this treatise generally contains comments denigrating the work, the author and the scholarly environment of the period based on the claim that it had already been proven at the time Hüseyin Efendi published his treatise, that a positive result could not be reached with the limited tools used in the solution. All this contemporary research is originated from a sole source, Salih Zeki Bey’s articles on the subject written a century ago, the accuracy of which is debatable in terms of its contents. This study focuses on the claims based on this common source as well as the history of the solution to the problem, and thus provides a correction to the erroneous information on the subject.