The very important topic of the transmission of the Greco-Roman knowledge to the medieval Islamic world has an interesting appendix concerning historiography. If the Arabic translations of the Greek philosophical and scientific texts are often aimed at the applied and theoretical science, the historical summaries taken from Greek and Syriac sources are placed immediately in the service of the Islamic historiography, which incorporates them within it, making redundant the existence of autonomous translations of historical texts.
It is evident that this translation and synthesis activities could involve only the Greek and Syriac works which were easily accessible and, above all, in line with the Islamic vision of the history. However, there is an exceptional case that deserve special attention: the so-called Kitāb Hurūšiyūš, that is the Arabic translation of the so-called Historiae adversus paganos by the Latin historian Paulus Orosius (IV/V century C.E.). It is a work of extraordinary importance, translated in al-Andalus in 10th century C.E. which left a deep mark on Western Islamic historiography, coming to constitute for many Arab intellectuals a unique and fundamental access door to the Graeco-Roman world. Like its Latin source, the Kitāb Hurūšiyūš is divided into seven books, but it is important to undernote that the work is not a mere translation of the Historiae adversus paganos, rather a mix of translation, abridgment and reworking of the original text. There are also large portions of the Orosius’ text that do not appear in the Arabic. It is hard to explain these omissions as part of a coherent editorial or ideological scheme: one wonders whether the translators consulted a corrupted source or omitted the passages on purpose. Besides the omissions, the so-called Kitāb Hurūšiyūš includes a number of passages that do not appear in the Latin text. The added material came mostly from a group of late-antique and early-medieval Latin sources. We do not know if these interpolations existed in the Latin source before the translation into Arabic. We can see a similar occurrence in a Latin manuscript of the Historiae adversus paganos from Madrid, which was written in Spain in the tenth century: in fact, in this manuscript several copyists present additional texts meant to supplement Orosius, whose narration ended in 417/18. As a conclusion of the present project, we provide the public with a fundamental tool: the complete translation of the Arabic text of the so-called Kitāb Hurūšiyūš and a rich historical-philological commentary that can constitute the starting point for further studies and research in various fields of knowledge (history, philology, anthropology, history of translation, history of mentality, etc.).