The process used is traditional lost wax casting. I made a couple of designs in wax, which were then cast, and the most successful one was used as the original to be reproduced.
The process involves pouring hot metal into a mold containing the wax shape, burning through the wax and leaving you with just the metal. Sprues were added to the wax shapes to direct the molten metal into all parts of the mold.
Reproductions of the selected original were what were used in the ceramic cast that the molten metal burned through.