15thc perception on swallowtail merlons?

[Pierre Dumont Himself]

17th century according to Italian Wikipedia, quoting Carlo Perogalli, Enzo Pifferi e Angelo Contino, Castelli in Lombardia, which I believe to be  the main reference work for castles in Lombardy. 
Castello di Bornato has swallowtails of a different material on top of the old merlons.

On a related note, please let me know if you can get your hands on this book or one of the following:
M. Merlo, Castelli, rocche, case-forti, torri della Provincia di Pavia, Pavia, 1971.
M. Viglino Davico, I ricetti del Piemonte, Torino 1979.
Tito Miotti, Castelli del Friuli (multiples volumes)
Publications for each region/province from the Atlante castellano (ongoing project)
Volumes for each region/province by the Istituto Italiano dei Castelli (ongoing)
E. Pagella, E. Rossetti Brezzi e E. Castelnuovo. Corti e città. Arte del Quattrocento nelle Alpi occidentali.
Oswald Trapp: Tiroler Burgenbuch (8 volumes)
Johanna Thali, Schrift als Bild. Wolfram-Studien XIX (article)
By hte way, it would be absolutely priceless if someone could contact Enrico Lusso and make him interested in the VM. @MarcoP, @Koen G. Not only is he the leading authority on castles in NW Italy, he also studies the history of cities in the Late Medieval and Early Modern periods, and has many collaborators. He should also be able to talk about arts, religion and literacy in this particular time period.