15thc perception on swallowtail merlons?

[Koen G]

Good find! It shows a portrait of Virgil (right) and a dedication of the book by the abbot to the patron saint of the abbey (left). This suggests that at the very least the composition of the left image was made by the abbey. 

I assume it is in fact late 12th century and 1282 is a typo.

I am unfamiliar with the cultural reasons why there would be swallowtail merlons in manuscript art around Munich at this time. Maybe this was associated with the Italian home of the Latin authors?