The a-speo methods were most actively used in the 17th C., being exploited by the Paternostrieri Guild at Venice; and also by Dutch glassworkers who learned this approach from Venetian masters.

The technique fell out of fashion—perhaps when the Suppialume (Lampworkers Guild) became proficient at making wound and trailed-decorated lampwork beads.

Nevertheless, in the late 19th or early 20th Cs., Venetians returned to making heated and manipulated drawn beads "a la lucerna" ("at the lamp"). So one could say (and I have) that these are "late a-speo beads."

JDA.