[Blog Post] Cracking a medieval code

[Helmut Winkler]

The replacement of vowels by nearby consonants was widely used, and is known as "Notae Bonifatiii".

It goes back at least to the 10th Century, but I don't know enough about the topic to be sure whether they are really related to St. Boniface, as one can read in various publications.

It is a tradition that goes back to Hrabanus Maurus, de inventione linguarum, Bonifatius is accredited with two sytems of cryptography, 1) replacing vocals by a system of dots and 2) replacing vocals a e i o u by b f k p x, as far as I can see this tradition is acvcepted as fact, because there are contemporary English examples, the replacement by consonants seems to go back to Antiquity. There are many examples from the 9th c., of both methods in the Althochdeutsche Glossen