I've been collecting and dealing for 15 years, and became a professional glass auctioneer about 6 months ago.
A few months ago I bought this beauty from an Auction in Lisbon.
Copier started making Unica pieces in 1923. At the beginning there were some unmarked items. Then he signed them with a number, then a year later he started adding a year letter in front of the number.
The whole story can be found in the excellent book 'Copier Unica' by Dieter Enke, but the earliest photo is of number 330.
Master craftsman Paul Spannenberg also has a site dedicated to unica
http://www.leerdamunica.nl/ on which private owners can register their Unica pieces. The lowest number shown is number 50.
You will have guessed by now that our Lisbon purchase was a bit special! On the bottom it has full marks and the number 13!
It's the most expensive and beautiful piece of glass I will probably ever own, so I thought I would share it with y'all.