Regarding the small blue bead with sparse millefiori—three points:

1) I would want to know how the bead was made, and whether it might be an a-speo bead (which would place it in the 17th C.).

2) Pizarro entered Northern Peru in late 1531 (the 16th century), bringing with him Early-Contact beads consisting of chevron beads, Nueva Cádiz, and millefiori beads—the latter being extremely rare and distinctive.

3) Over the previous four years I have continued to be exposed to early trade beads having been recovered in Peru. I have become convinced that this corpus includes beads made as late as the 17th C. (such as a-speo beads).

So, for these reasons I would question a "15th C. origin" for the bead we are discussing.

JDA.