Charlemagne’s biographer, Einhard, as well as one of his key courtiers, Alcuin, flattered the ruler with praise for his interest, indeed expertise, in science generally and astronomy in particular. In 809 CE a group of computistic scholars, apparently under the leadership of Adalhard of Corbie, gathered at Aachen and produced a handbook containing both texts and images that were intended to be helpful in understanding the calendar and, on the basis of that knowledge, of properly arranging the liturgical year.

The Carolingians embarked on a program of spiritual and societal regeneration. Correct worship was essential for that program’s success. The study of the liberal arts was of great spiritual benefit and this was especially true of astronomy because of its link to worship. Studying the heavens and their orderly processes inevitably led one from creation to the creator. Ramírez-Weaver speaks of “scientific soteriology.” The study of astronomy contributed to the salvation of individuals and of society as a whole.

The “Handbook of 809” is not extant, but several “princely” copies, or versions, were prepared in the years after the Aachen conference. These manuscripts provide sufficient evidence to enable scholars to reconstruct the handbook, and Ramírez-Weaver does a good deal of reconstructing. His primary focus rests on one of the later copies, specifically the one prepared, perhaps around 830, for Bishop Drogo of Metz (Madrid, Biblioteca Nacional, MS 3307). Drogo was an illegitimate son of Charlemagne who was named to the see of Metz in 823 by Louis the Pious, Charlemagne’s son and successor. Another copy (Vatican Library, Vat. lat. 645) was apparently made for Drogo’s brother Hugo, who was abbot of Saint-Quentin. One more (Vatican Library, Reg. lat. 309) was made for Louis, an illegitimate grandson of Charlemagne, who was for many years abbot of Saint-Denis. Finally, a copy now in Monza, Italy (Biblioteca Capitolare, cod. F–9/176), was, Ramírez-Weaver speculates, prepared for Hubert, the brother-in-law of Lothair II. The attributions to Hugo and Louis seem plausible to me, given that the relevant manuscripts were copied in the monasteries over which they presided. The Monza manuscript was apparently copied at Lobbes (Belgium). Hubert was for a time abbot of Lobbes. Presto! The “princely” Monza manuscript was made for someone with Carolingian connections, and only Hubert seems to fit. I have no alternative to suggest, but I am not convinced. Lothair II spent decades trying to divorce Hubert’s sister Theutberga. What would anyone have gained by rewarding Hubert with a luxury book? Drogo was a major player in ninth-century secular and ecclesiastical politics. He was a man whose favor would have been avidly sought. Hugo and Louis were much less prominent. I am also not quite in agreement with Ramírez-Weaver’s designation of all these books as “princely.” The books are pretty spectacular, but their alleged recipients are borderline obscure—apart from Drogo. I do not think that it necessarily follows that because the books were prepared in a particular place, they were presented to the abbots of those places. Compare the copies of his De Laudibus Sanctae Crucis, with their beautiful carmina figurata, that Hrabanus Maurus gave to Louis the Pious, Pope Gregory IV, Archbishop Otgar of Mainz, and Margrave Eberhard of Friuli, among others. Those were princely recipients.

I struggled a bit with the book’s organizational structure, but I found its central argument to be convincing. Drogo’s handbook, like the other books that descended from the handbook of 809, was a practical manual treating the liberal art of astronomy. Its audience comprised teachers in ecclesiastical schools and their pupils. By means of a complex program of texts, diagrams, and images, the handbook aimed to present a Christian, and indeed specifically Carolingian, picture of the heavens. Fundamentally, the program permitted the determination of the first full moon after the vernal equinox—in other words, it permitted the determination of the correct date for Easter. Once the date of Easter was fixed, the rest of the liturgical year could be organized correctly. In addition, dates for planting and harvesting could be settled as well. And the stars had always been guides to navigation.

Thus far we have a nice argument that will be of interest to intellectual historians and particularly to historians of science. Ramírez-Weaver does not stop there. He works his way through a series of discussions designed to show that the art-historical dimensions of Drogo’s handbook are original and revealing. He notes that art historians have not paid much attention to the Madrid manuscript. In part, this is due to a persistent—although, I think, increasingly diminishing—view that when faced with classical models the Carolingians were faithful copyists who added nothing original. Ramírez-Weaver has interesting things to say about the Warburg Institute and about Fritz Saxl and Erwin Panofsky regarding their denial of creativity to Carolingian artists and commitment to iconography. Historians of science, meanwhile, have mainly been interested in the texts in the handbook and the ways in which they transmit ancient astronomy. So Ramírez-Weaver proposes to give the first comprehensive study of Drogo’s handbook with, at its heart, an art-historical analysis of its images and diagrams.

The materials with which they were working posed some real challenges for the Carolingians. Basically, they had to contend with illuminated manuscripts of the Phaenomena of Aratus and with Pliny’s Natural History. These materials were full of pagan mythology that was at best a distraction and at worst a danger to the soul of the Christian. The artists who prepared the images in Drogo’s handbook worked with great skill, but they did more than just produce beautiful images. They performed feats of exegesis as they subtly altered the Aratus images so as to teach about the heavens while simultaneously trimming the pagan content and associations of the sources. In a lengthy section (84–119) Ramírez-Weaver provides an excellent art-historical study of the images of the constellations. His discussion is aided by a set of seventeen beautifully reproduced plates. The kind of exegesis accomplished by the painters builds on a distinction drawn by Isidore of Seville between scientific astronomy and superstitious astrology. Instead of mindless but faithful copying, one sees original and deliberate argumentation accomplished by means of slight alterations of the models.

Ramírez-Weaver joins in some other conversations too. He parts company with the rigid systematization of Wilhelm Koehler and Florentine Mütherich, who tried to group Carolingian manuscripts into coherent schools. Instead, he builds on an argument advanced by Lawrence Nees in 2001 proposing that there were professional and highly skilled painters who moved from place to place to fulfill commissions. Ramírez-Weaver identifies four painters in Drogo’s handbook, two masters and two assistants. Master number two was the most gifted of the group. There is no reason to think that any of the four was permanently resident in Metz. He also notes that there were demonstrable connections between Metz and Reims but argues that it is better to think of “mutual aesthetic influence and interaction” (175) than of schools. Ramírez-Weaver also builds on work by Hans Belting, John Mitchell, and Nees to show the impact of Italian painting on Carolingian masters. In other words, it is necessary to look far and wide for analogues, influences, and sources and to avoid pigeonholing art and artists into schools. The pictures and texts in Drogo’s handbook created a cohesive, ordered presentation of the cosmos and an irreproachably Christian interpretation of the heavens. It will be interesting to see how scholars react to this dimension of Ramírez-Weaver’s work. I am persuaded.