Editor’s Introduction: The DMNES staff are super delighted to host a two-part guest blog by Dr. Joanne Edge. Dr. Edge’s PhD research focused on “onomancy”, a type of medieval magic based in a person’s name, a topic we thought would be of interest to readers of the blog!
Part 1 is below; Part 2 is here.
What’s really in a name? Onomancy in the Middle Ages (Part 1)
Dr. Joanne Edge, Latin Manuscripts Cataloguer at the John Rylands Library, University of Manchester
What can our names tell us about our fate? According to some modes of medieval thought, quite a lot. Here, I will describe a divinatory practice called onomancy. Onomancy – haplological for onomatomancy – means ‘divination by names’, and, if surviving manuscript numbers are any indication, the most common form of divination in the later Middle Ages.1 Divination is an ancient and cross-cultural phenomenon. Benedek Láng provides a succinct definition: it is ‘the procedure of foretelling the future and discovering hidden knowledge through the interpretation of signs’.2 There are many forms present in medieval sources, which fall into two categories – ‘active’, or set up (such as dice throwing); and ‘passive’, or spontaneous (such as omens and portents). Onomancy falls into the first category, along with other types of divination such as geomancy (drawing dots), chiromancy (palm-reading) and bibliomancy (randomly opening books, usually the Bible).
To demonstrate how onomancy works, I will use the example of the most commonly-occurring variety in medieval manuscripts, the Sphere of Life and Death or Sphere of Pythagoras. Here is an example from a manuscript produced in England c. 1375, now Oxford Bodleian Library MS Digby 46. The Sphere is most often used to predict whether a sick person will live or die, but is also used for any question about an individual requiring a yes/no answer. The six-line verse at the bottom of the page instructs the operator to take the name of the sick person and convert the letters of their name into numerical equivalents (which are found in the two outer rims of the diagram). You add these up into a total. Add the number of the day of the moon on which they first fell sick (a number between 1-30), and the number of the planetary weekday (each day has a corresponding number, usually located in or next to the diagram). These three numbers are added into a grand total and divided by 30. If the remainder is in the top hemisphere, the person will live, if in the bottom, they will die. The three columns of numbers indicate whether recovery or death will be quick, medium or slow.
The Sphere is first attested in a Greek papyrus made in the fourth century CE, but it probably has much older roots. It was translated, and the earliest surviving example in Latin dates from around 805 CE.3 However, there was an inherent problem with translation into Latin. Every Greek letter has a corresponding number, but not every Latin letter does. This led to confusion as medieval Latin translators and copyists tried to find the ‘correct’ original and ascribed numbers to letters without any rationale. The result was that multiple versions of the Sphere survive with different number-letter correlations and different remainders in the centre. Another problem was posed by non-Latin letters like K and W. Most Spheres leave these out, but the copyist of a physician’s almanac, now London British Library MS Harley 5311, made in 1406, added:
Note that if there is a double letter taken from another language it should not be two numbers but one, so for William first V and then I should be used and so too of the rest.4
So, using a Sphere was not an exact science, and there was plenty of space for ambiguity.
The Sphere was not the only onomantic method circulating in medieval manuscripts. Here is an experiment found in at least four manuscripts of English provenance produced in the fourteenth and fifteenth centuries:
If you want to know who will die first, a husband or wife, calculate their names, and find out the numbers of the letters and divide by nine. If the number is even the wife will lead the husband to the grave. If odd the husband will be buried by the wife.5
It is not difficult to imagine why such knowledge might have been desirable to either party in a marriage!
Yet more onomantic texts survive from the later Middle Ages, such as the Victorious and Vanquished, which pits two values against one another. This was used for working out which of two generals or parties might succeed in a battle or duel.6 But by far the most commonly-surviving onomantic method is the Sphere.
 For an overview of onomancy see Joanne Edge, Nomen omen: The Sphere of Life and Death in England, c.1200 – c.1500, Ph.D. thesis, Royal Holloway, University of London (2015).
 Benedek Láng, Unlocked Books: Manuscripts of Learned Magic in the Medieval Libraries of Central Europe (University Park: The Pennsylvania State University Press, 2008), p. 123.
 Cologne, Erzbischöflichen Diözesan-und Dombibliotek: MS 83.II, f. 218v.
 My translation. London, British Library MS Harley 5311, leaf I.
 My translation, Oxford, Bodleian Library MS 177, f. 1v.
 On this tract see Charles Burnett, “The Eadwine Psalter and the Western Tradition of the Onomancy in Pseudo-Aristotle’s Secret of Secrets”, Archives d’histoire doctrinale et littéraire du moyen âge 55 (1988), pp. 143–67.