Here are the results of the bidding:
everybody was to pessimistic.
The oldest stone along one of the Dutch borders is:
Bordermarker nr. 20 near De Lutte in the province of Overijssel.
This stone dates back to around 1480 !
My source is this book:
Monumenten in Nederland, 3 - Overijssel.
Ronald Stenvert, Zwolle (Waanders), 1998.
Quote:
"De zandstenen grenssteen nr. 20 dateert uit omstreeks 1480 en draagt aan
weerszijden de wapens van het graafschap Bentheim. Het is de oudste
grenssteen langs de Nederlandse Rijksgrens."
My translation:
The sandstone borderstone nr. 20 dates back to around 1480 en carries the
coat of arms of Grafschaft Bentheim at both sides. It is the oldest
bordermarker along the Dutch border.
I invite you to visit my website
http://leden.tref.nl/~veenhh/borderland.htm
- enter BorderLand, click on "national" and look for Overijssel.
There is also a link to a (topo)map.
Gl
Harry ten Veen