The Millefiori technique
Or "thousand flowers", is an ancient artisan technique consisting of creating a particular pattern of drawings inside a tube, based on layers of color and shape that make up said tube, like an elongated mosaic from which exactly the same slices are obtained with which the pieces will be created. The diameter of the tube decreases or widens on a whim, maintaining the proportion of the shapes and colors of the drawing.
The manufacture of these "tubes / mosaic" dates back to ancient Rome, some were found in the eighteenth century and were used in thin slices for Anglo-Saxon jewelry from the Sutton Hoo treasure. (!!!)
The technique is absolutely linked to the famous Venetian Murano glass, where the tinted glass technique for making beads was reinvented and reintroduced, these were also called "mosaics" until the term "Millefoiri" appeared in the Oxford dictionary from 1849.
As it is not possible to draw a continuous line from the Romans to the Venetian Renaissance, it is possible that the great glass boom was due to the commercial and cultural relations between Byzantium and the whole of the Mediterranean.
As an example of its great expansion, there were in Venice between 1500 and 1525, 24 factories and in 1606 there were already 251 workshops that were dedicated to its production, which was a secret, so to avoid copies between workshops, they prohibited under pain of death glass artisans to divulge the secrets of the realization and even to leave the Island to establish new workshops.