A note to self from Richard Rudgley’s Barbarians: Secrets of the Dark Ages: make green ink by putting copper in vinegar or wine, scraping off the green stuff and mixing it with egg white (page 215). Yellow in the Lindisfarne Gospels came from arsenic – not likely I’ll ever be drawing with arsenic. Black was easy: soot with gum or oak galls.

When the Venerable Bede wrote his Ecclesiastical History of the English People around 731, historians had a tough time. Much like the Japanese calendar today, the English calendar depended on who one’s ruler was. Thus, in the patchwork England of the so-called Dark Ages, one parish might be celebrating Easter while a neighbouring one was still trudging through Lent. This is an example that Richard Rudgley used in his book Barbarians: Secrets of the Dark Ages. The Venerable Bede, to write his history, began using the innovative Anno Domini dating system.

The book describes some of the other math genius tricks up the Venerable Bede’s sleeves:

Not only did he have to reconcile diverse chronological systems, he had to find a means to calculate them. The Arabic numerals we use today were not known in the world of Bede and his contemporaries. Roman numerals made complex calculations extraordinarily difficult and so Bede taught a method of calculation using the fingers and other parts of the body. By moving the fingers into different positions it was possible to represent all the numbers up to 9,999. By employing the elbows, shoulders and other body parts you could get up to a million!

(Page 207)