The Vintage Wrist Watch Company has dated this piece to the 1910s.
The watch has a stem-winding movement, signed Björn, which is working nicely.
The movement carries the Zenith serial number 2,401,323 which dates it back to 1919.

The movement is protected by an inner hinged cover.
The watch measures 52mm diameter excluding the winding stem and loop. The case is 800 silver with rose gold wash detailing, a style of case called galonne, popular in the Scandinavian countries at the beginning of the 20th Century and we assume Zenith used the name Björn to appeal to Scandinavia consumers. The case is in beautiful condition with nice crisp engine turned detail to the hinged case back and unusually the gold wash is still in place, so often it wears off over the years.

The inside of the case back has the Björn logo. This was registered by Zenith in 1897, and also by Carl Jürs & Krohn of Hamburg, possibly so the same watch could be retailed in Germany.
The glass lens is in good condition, just a few little marks but nothing serious at all... some reflection showing in the photos.
The dial is signed Björn. It all looks very nice to the naked eye. If viewed through a magnifying loupe there are some very faint hairlines.
The watch comes in a new presentation box.
The Vintage Wrist Watch Company has dated this piece to the 1910s.
Specialists in antique and vintage wrist watches and pocket watches
You can view the stock and full dealer information on the The Vintage Wrist Watch Company Profile Page