One of the earliest pieces of evidence for the reception of Kalīla wa-Dimna is a curious and scarcely known animal fable-like booklet attributed to Sahl b. Hārūn (d. 215/830). He was a personality of early Abbasid times, an Iranian Shuʿūbī, probably with Shīʿī sympathies; a boon-companion of Hārūn al-Rashīd (r. 170–193/786–809); and secretary to the vizier Yaḥyā al-Barmakī (d. 158/808), whose dramatic fall he survived. Under the caliph al-Maʾmūn (r. 198–218/813–833), he was connected to al-Ḥasan b. Sahl (d. 234/850) and became a leading figure of the bayt al-ḥikma, the caliphal palace library famous for its rich collection of Persian and Greek books. His younger contemporary al-Jāḥiẓ (d. 255/868) praised him as superior orator, master of style, and author of many books. The Panther and the Fox (al-Namir wa-al-thaʿlab) is one of Sahl’s few original works that have survived. It is preserved, probably as an abridgment, in an undated single manuscript, and it has been edited twice: by A. Q. Mehiri in 1973, and by M. al-Kaʿbī in 1980. The booklet seems not only to emulate Kalīla wa-Dimna by combining the genre of the animal fable with that of the mirror for princes, but it also quotes whole passages from the earlier work. However, there are significant differences between the texts: for instance, al-Namir wa- al-thaʿlab is much more “arabo-islamized.” We find abundant qur’anic quotations, Arabic poetry, and well-known proverbs (amthāl); the animals bear Arabic names, e.g., Abū l-Ṣabbāḥ Marzūq; the structure is linear and less diegetic, but rather dialogical and epistolary (no framing narratives or embedded stories); there is use of rhymed prose (sajʿ) in introductory passages and longer sermons; and, generally speaking, the message is more moralizing. These characteristics invite a comparison of the two works and a new exploration of their relationship, so that we might better understand the early reception history of Kalīla wa- Dimna. The questions to be addressed include the following: Was al-Namir wa-al-thaʿlab an Islamized and culturally translated version of a new genre initiated by Kalīla wa-Dimna? Why did later authors, including al-Jāḥiẓ, Ibn al-Nadīm, and al-Masʿūdī, consider al-Namir wa-al- thaʿlab an “imitation,” or even a “better version” of Kalīla wa-Dimna? Where did they see similarities? And what could be the reasons why Kalīla wa-Dimna became such a successful classic, whereas al-Namir wa-al-thaʿlab fell into almost complete oblivion?