Some makers theorize that the early Cremonese makers inlaid purfling in three separate, unglued strips, the way French makers of the 1800s did. That has never appeared to me to be the case, and here’s one Cremonese violin, a Brothers Amati from 1605, where there’s obvious proof that the purfling was glued together before it was bent and glued in place. Notice the compression folds on the inside of the curve (the outside, black, purfling strip).