One of the interesting things about finding pottery on the beach, especially if it has a pattern or letters on it, is doing a bit of research to find out what it was and where it came from. I've found two pieces (on different days) with NASSAU stamped on them and this is what I've found out.
These pieces are parts of clay bottles once filled with mineral water, from the Duchy of Nassau. This Duchy was part of the Confederation of the Rhine, later to become the German Confederation and existed for about 60 years (1806-1866).
The mineral water originates for a well in Niederselters/Taunus Mountains -
*The following information is translated from Wikipedia*
* The Well was discovered in 1536 and soon the water was said to have curative effects. In the 18th century, the water was verifiably exported to England, Scandinavia, Russia, North America and Africa. Between 1806-1866, the export of seltzer bacame the Duke of Nassau's most important source of income. *
The bottles carrying the mineral water were made of saltglazed stoneware. Straight-sided, and circular with quite a short neck. Each jug had a single applied handle which loops from just below the base of the neck to the base of the shoulder photo to follow).
Nassau Selter bottles carried an impressed seal with SELTERS/NASSAU around a German eagle that contains the initials, F.R., on a shiled on his chest. These bottles were a cottage industry in the Westerwald Mountains area, known as the 'jug baking land/district'. Under the handle of each bottle is stamped the first initial of the jugmaker's location and the person's individual number.
Because of the competition from glass container, the jug trade declined by the end of the 19th century and was reduced to 49 jugmakers by 1926.