The roof of the Archaic Temple of Poseidon (early 7th century B. C.) at the Sanctuary of Poseidon on the Corinthian Isthmus in Greece was covered by unusually large terracotta tiles. The construction of a stone temple with a tile roof represented a major advance in building design. The tiles themselves are representative of the growth in technology at that time. Reproduction of the tiles was recently undertaken as a demonstration of the tools, skills, and man power requirements of the new technology. A relatively small group of men using local materials could make all of the tiles and the kiln(s) to fire them in less than two years. The major innovation was the design of the mold.