Bad day at the office? Medieval calendars could warn you not to get married, start a journey, undergo medical treatment — or apparently eat a goose.
Some days were thought to carry danger before anything had actually happened. The difficulty was knowing whose list to trust.
THE SHORT ANSWER
Medieval writers inherited and copied traditions which treated particular dates as unsuitable for important undertakings. Often called “Egyptian days”, these warnings mixed calendrical learning, medical ideas and religious explanations.
They were not one universally agreed system. A common arrangement identified 24 days, while other texts singled out three especially dangerous days or supplied longer lists. Their survival documents the belief, not the reality of the danger.
WHAT WE KNOW
The name is older than the Middle Ages. Historian Don C. Skemer notes that dies aegyptiaci was used by at least the fourth century AD. One enduring arrangement placed two ominous days in every month. Some versions became more precise still, identifying a dangerous hour.
But the striking 32-day list comes to us through a later witness.
In The Book of Days, published in the 1860s, Robert Chambers reproduced a calendar he described as dating from Henry VI’s reign. Its warning covered marriage, journeys, new work, illness and injury. January alone supplied seven perilous dates.
That is evidence for a particular list reported by Chambers, rather than proof that everyone in medieval Europe followed the same schedule.
HOW IT BECAME A HABIT
Warnings could travel with useful information.
A liturgical calendar described by manuscript specialists Les Enluminures places verses about Egyptian days alongside saints’ feasts and the calculations needed to organise the church year. The dangerous days are marked in red.
This makes their setting revealing. A reader did not necessarily encounter them in a separate book of supernatural terrors. They could appear within the familiar apparatus for keeping track of time.
Copying a calendar offered a straightforward way to copy its warnings too. A verse helped make the information memorable; a coloured entry made it easy to find.
THE STORY EVERYONE TELLS
The name seems to promise a neat explanation: Egyptian astrologers discovered the unlucky dates, and medieval Europeans inherited their knowledge.
That was one explanation attached to the tradition. Another connected the days with the biblical plagues of Egypt.
Ancient Egypt certainly had calendars of favourable and unfavourable days. The British Museum holds one dating from around 1225 BC, with assessments linked to mythological events.
But that does not establish an unchanged timetable passed directly from pharaonic Egypt into every medieval European calendar. Similar beliefs, inherited names and claims of ancient authority are different kinds of evidence.
And then there is the goose.
WHAT THE EVIDENCE ACTUALLY SAYS
The goose warning is not merely a Victorian collector’s colourful anecdote.
Bodleian manuscript Digby 86, a late-thirteenth-century miscellany, contains a warning about three perilous lunar days. Its text predicts death on the fortieth day after eating goose on any of them.
The warning is attributed to Bede, but an attribution within a manuscript does not establish that Bede wrote it. Nor does the text explain why goose should be dangerous.
We can document the instruction. Its rationale remains uncertain.
Other manuscripts show how closely these warnings could sit beside medicine.
The University of St Andrews’ Corpus of Early Medieval Latin Medicine describes a booklet containing a 24-day list and a separate warning about three critical Mondays. Bloodletting, travel and vineyard planting appear among the prohibited activities.
One passage explains danger through the condition of the veins; another invokes Pharaoh and Egypt. These are explanations within the historical texts, not findings supported by modern medicine.
Our evidence label is therefore WELL SUPPORTED for the existence of the tradition. It does not mean the predicted deaths were real, the dates agreed, or everyone obeyed.
A calendar tells us what someone preserved and recommended. Establishing how consistently households, travellers or practitioners followed it is a harder task.
WHY IT STUCK
A dangerous date offered an appealing kind of reassurance: perhaps misfortune could be avoided simply by waiting.
That is an interpretation of the belief’s attraction, rather than a motive we can assign to every reader. Still, it helps explain why a precise warning might feel useful even when its foundations were uncertain.
The language survived more successfully than the timetable.
“Dismal” developed through Anglo-French dis mal from Latin dies mali: evil or unlucky days. Its meaning eventually broadened into the familiar sense of gloom.
When we describe a thoroughly dismal afternoon, we are using a word with a much more threatening history.
At least we no longer have to check the date before ordering the goose.
RELATED CURIOSITIES
Why Is Friday the 13th Supposed to Be Unlucky?
Why Is the Number 13 Considered Unlucky?
SOURCES & FURTHER READING
Robert Chambers, The Book of Days — “Unlucky Days”, January 2. A nineteenth-century compilation reporting earlier calendars and warnings.
https://www.thebookofdays.com/months/jan/2.htm
Don C. Skemer, “Armis Gunfe: Remembering Egyptian Days”, Traditio. Scholarly discussion of calendrical omens and methods of remembering them.
University of St Andrews, Corpus of Early Medieval Latin Medicine — “MMOTM 8: Paris BN NAL 1616”. Discussion of unlucky-day texts within a medical and calendrical booklet.
https://cemlm.wp.st-andrews.ac.uk/2024/05/31/mmotm-8-paris-bn-nal-1616/
Medieval French Lunar Almanacs — “Oxford, Bodleian, Digby 86, Yearly Perilous Moon Days”. Manuscript description, transcription and translation of the goose warning.
https://lunarybooks.omeka.net/items/show/51
Les Enluminures, Medieval Text Manuscripts — “Liturgical Calendar”. Description of Egyptian-day verses and red calendar entries.
https://www.textmanuscripts.com/medieval/liturgical-calendar-60888
British Museum — Papyrus EA10184,6. Ancient Egyptian calendar of lucky and unlucky days.
https://www.britishmuseum.org/collection/object/Y_EA10184-6
Michael Quinion, World Wide Words — “Egyptian days”. Discussion of the tradition and the development of “dismal”.