Three Aluminia Christmas Plates. From 1906, 1925 and 1919. Diameter 16.5 cm. Excellent condition. In the 1880s when production at the Royal Copenhagen factory was dropping to a dangerously low level they were taken over by Aluminia (founded 1863), successful makers of earthenware, and since that time the two ranges, earthenware and porcelain, have been running in tandem.