It has hitherto been supposed that the earliest allusion to ‘Umar Khayyām is that contained in the Chahār Maqāla of Niẓām-i‘ Arūḍī, which was written in A.H. 552, and the second allusion in point of date that contained in the Nuzhat al-Arwāḥ of Muḥammad Shahrazūrī, written about the middle of the seventh century. The latter account was edited, together with a subsidiary Persian version and Russian translation, by Professor Zhukovsky in al-Muzaffariya (St. Petersburg, 1897, pp. 327–31). Now this account of ‘Umar was taken almost verbatim, but with several extensive omissions, from the Ta’rīkh Ḥukamā’ al-Islām of Ẓahir ad-Din al-Bayhaqi, which was composed before A.H. 549, and therefore antedates by some years the noticein the Chahār Maqāla. We are indebted to Professor Weil for the kind loan of the unique manuscript of this work, now in the Berlin University Library (Petermann, ii, 737), from which the following notice has been extracted.