Union was founded in 1904 and made its own bicycles since 1911. Low image (it was considered a farmer's bike), bad and criminal management and problems with the bicycle cartel (that prevented price dumping and protected small bicycle shops) caused the Union brand to disappear in 2005. The factory makes B-brand bicycles now.
More info (in Dutch): www.rijwiel.net/unionn.htm
You can see the obligatory red reflector and white-painted end of the mudguard.