I.B.Tauris in association with the Institute of Ismaili Studies A distinguished scholar, author and statesman, al-Mu'ayyad fi'l-Din al-Shirazi (c.997-1078 CE) lived during one of the most turbulent periods in Islamic history. The 11th century was characterized, among other things, by an acute struggle for supremacy between the Sunni and Shi'i branches of Islam, represented politically by the Abbasid and Fatimid caliphates. Al-Mu'ayyad was a Fatimid Ismaili da'i (missionary) who first rose to prominence in theservice of Abu Kalijar, the Buyid ruler of the Fars region in south-west Persia, which was then part of the Abbasid empire. Al-Mu'ayyad's proselytizing activities, however, incurred the hostility of the local political and religious establishment. After enduring much persecution, he was forced to flee his homeland for Fatimid Egypt, where he offered his services to the Imam-caliph al-Mustansir bi'llah. Despite initial setbacks, al-Mu'ayyad's outstanding intellectual and literary skills soon came to be recognized and he was appointed to important positions in the Fatimid administration. Eventually, he attained the highest ranks in the religious hierarchy, including that of chief da'i and director of the Dar al-'Ilm (House of Knowledge) academy in Cairo. During the twenty years he served in these positionsuntil his death at an advanced age, he won widespread acclaim for his scholarship and sagacity, as well as his authorship of a number of theological, devotional and literary works. The Diwan of al-Mu'ayyad al-Shirazi is notable for its exceptional poetic quality as well as a personal testimony of his career as a Fatimid da'i. Comprising a total of 62 qasidas (odes) of varying length, the Diwan covers a wide range of political and religious issues, from al-Mu'ayyad's intellectual disputations and personal experience of persecution to devotions in praise of the Prophet Muhammad and his family. In doing so, he provides a rare, first-hand description of some of the political and sectarian tensions that polarized the Muslim community of his time. Al-Mu'ayyad's poetry is rich in imagery, rhetorical techniques and symbolic allusions to the esoteric lore of the Fatimid Ismailis. This first complete English translation of the Diwan seeks to recapture some of the poetic power and flavour of what is undoubtedly one of the masterpieces of medieval Arabic literature.