Named a Best Book of 2020 by The Telegraph, The Times, and BBC History Magazine An illuminating guide to the scientific and technological achievements of the Middle Ages through the life of a crusading astronomer-monk. "Falk’s bubbling curiosity and strong sense of storytelling always swept me along. By the end, The Light Ages didn’t just broaden my conception of science; even as I scrolled away on my Kindle, it felt like I was sitting alongside Westwyk at St. Albans abbey, leafing through dusty manuscripts by candlelight." —Alex Orlando, Discover Soaring Gothic cathedrals, violent crusades, the Black Death: these are the dramatic forces that shaped the medieval era. But the so-called Dark Ages also gave us the first universities, eyeglasses, and mechanical clocks. As medieval thinkers sought to understand the world around them, from the passing of the seasons to the stars in the sky, they came to develop a vibrant scientific culture. In The Light Ages, Cambridge science historian Seb Falk takes us on a tour of medieval science through the eyes of one fourteenth-century monk, John of Westwyk. Born in a rural manor, educated in England’s grandest monastery, and then exiled to a clifftop priory, Westwyk was an intrepid crusader, inventor, and astrologer. From multiplying Roman numerals to navigating by the stars, curing disease, and telling time with an ancient astrolabe, we learn emerging science alongside Westwyk and travel with him through the length and breadth of England and beyond its shores. On our way, we encounter a remarkable cast of characters: the clock-building English abbot with leprosy, the French craftsman-turned-spy, and the Persian polymath who founded the world’s most advanced observatory. The Light Ages offers a gripping story of the struggles and successes of an ordinary man in a precarious world and conjures a vivid picture of medieval life as we have never seen it before. An enlightening history that argues that these times weren’t so dark after all, The Light Ages shows how medieval ideas continue to color how we see the world today.

First published as a special issue of the journal Medieval Encounters (vol. 23, 2017), this volume, edited by Josefina Rodríguez-Arribas, Charles Burnett, Silke Ackermann, and Ryan Szpiech, brings together fifteen studies on various aspects of the astrolabe in medieval cultures. The astrolabe, developed in antiquity and elaborated throughout the Middle Ages, was used for calculation, teaching, and observation, and also served astrological and medical purposes. It was the most popular and prestigious of the mathematical instruments, and was found equally among practitioners of various sciences and arts as among princes in royal courts. By considering sources and instruments from Muslim, Christian, and Jewish contexts, this volume provides state-of-the-art research on the history and use of the astrolabe throughout the Middle Ages. Contributors are Silke Ackermann, Emilia Calvo, John Davis, Laura Fernández Fernández, Miquel Forcada, Azucena Hernández, David A. King, Taro Mimura, Günther Oestmann, Josefina Rodríguez-Arribas, Sreeramula Rajeswara Sarma, Petra G. Schmidl, Giorgio Strano, Flora Vafea, and Johannes Thomann.

A Treatise the Astrolabe by Geoffrey Chaucer is the work of an avid amateur astronomer who happened also to be England’s greatest medieval poet. A user of the astrolabe can plot the movement of the stars, tell time, and calculate numerous other results. Chaucer translated and revised a standard Latin treatment of the astrolabe. His treatise, which is generally regarded as one of the first technical manuals in English and a model of how technical manuals should be written. Not since 1872 has a free-standing edition of A Treatise the Astrolabe been published. Thanks to the expertise of its editor, Sigmund Eisner, who supplies sixty-eight illustrations, this Variorum edition provides a more detailed exposition than previously available. Eisner’s extensive labors result in the first complete record of textual variants found in the thirty-two surviving manuscripts of the work and in all the major printed text published between 1532 and 1987. This landmark edition also presents a thorough digest of all published commentary on Chaucer’s treatise. Amplified by sixty-eight illustrations, this variorum edition of Chaucer’s A Treatise on the Astrolabe provides a more detailed exposition of the treatise than has ever before been available.

Modern society owes a tremendous amount to the Muslim world for the many groundbreaking scientific and technological advances that were pioneered during the Golden Age of Muslim civilization between the 7th and 17th centuries. Every time you drink coffee, eat a three-course meal, get a whiff of your favorite perfume, take shelter in an earthquake-resistant structure, get a broken bone set or solve an algebra problem, it is in part due to the discoveries of Muslim civilization.

In the Middle Ages the astrolabe was the best known and most widely used astronomical instrument both in the Islamic world and in the West. The oldest extant description of the construction of this instrument was written by the well-known Arabic astronomer al-Farghani (Baghdad, ca. 856). His treatise is especially valuable because of the tables it contains to enable an artificer to draw the various circles and arcs on the instrument. The Arabic text of this work, including the tables, is presented here for the first time in a critical edition, accompanied by an English translation and a commentary reproducing al-Farghani's reasoning in modern mathematical notation.