Decorating glass vessels with glass threads and trails was already typical of early medieval glass. The tradition continued when small glass bottles and bowls were decorated in the forest glasshouses of the 12th and 13th century. Only little glass tableware of that time has been discovered in southern Scandinavia, and not much has survived in Central Europe either. The vessels are made of poorly-preserving potash glass, which was produced in German forest glasshouses. The found fragments are almost always very small and they have become opaque and crystallised ΓÇö it is very difficult to identify the substance as glass. Such shards have been discovered, for instance, in the excavations conducted in Roskilde and L├╢d├╢se.
