 All ancient heating systems, including hearths, furnaces, and stoves, operated primarily through convection.Fixed central hearths, which were first excavated and retrieved in Greece, date back to 2500BC, while crude fireplaces were used as early as the 800sAD and in the 13th century, when castles in Europe were built with fireplaces with a crude form of chimney.Many developments took place since then, including the creation of stoves with thermostatic control in 1849, the rise of numerous cast iron stove manufacturers during the Civil War, and publication of the very first manual on fireplace design called "Mechanique du Feu" in 1973.