Collection of the Principles and Objectives in the Science of Timekeeping


Abu al-Hasan ʻAli al-Marrakushi was a 13th-century mathematician, geographer, astronomer, and timekeeper. He was born in Marrakesh, in present-day Morocco, but immigrated to Mamluk Egypt, apparently fleeing the upheaval in Arab Spain and the Maghreb under the Almohads. He worked as a muwaqqit (timekeeper) in Cairo, where he wrote his major work, Jāmiʻ al-mabādiʼ wa al-ghāyāt fī ʻilm al-mīqāt (Collection of the principles and objectives in the science of timekeeping), an encyclopedia of practical astronomy preserved in this manuscript. The work, written between 1276 and 1282, is considered “the single most important source for the history of astronomical instrumentation in Islam.” It is divided into four books, called funun (arts), which are further divided into chapters. In the first book, comprising 67 chapters, al-Marrakushi discusses calculations on a range of issues, including trigonometry, geography, solar motion, prayer times, and the fixed stars. The second book, consisting of seven chapters, deals with the construction of such instruments as spherical astrolabes, sundials, al-rubʻ al-mujayyab (the trigonometric grid), as well as different types of quadrants. The third book comprises 14 chapters, and covers the use of specific instruments; and the fourth is a quiz in four chapters intended to train students. The manuscript is rich in illustrations, especially of astronomical instruments. It also contains tables in black and red ink along the text. Al-Marrakushi's work influenced astronomers and timekeepers for centuries. A French translation of the work by astronomer and orientalist J.J. Sédillot was published posthumously by his son Louis-Amélie Sédillot in 1834. The manuscript copy presented here was written in nastaʿliq script by an unknown scribe and has widespread water damage. It was produced in 1586, possibly in Turkey, Egypt, or Syria.

Last updated: September 29, 2017