Figure scales are expressed two ways, either as a simple measurement, e.g. 25mm, defining how high a figure of a normal man or woman stands or as a ratio, e.g. 1/48th, defining how big a model vehicle, vessel, aircraft, or construction is in relation to the real thing. The emphasis here is on the former classification with the latter provided where possible as an approximate comparison.
The following is a brief history of modern wargaming told in quotes from various wargaming books & authors:
“It was in Europe that the early forms of wargaming gradually took on a more sophisticated appearance. During the Seventeenth Century several variations on the basic game of chess were introduced. During the Eighteenth Century a number of games were introduced into France which departed from the idea of pieces and which used series of cards designed to impart basic military knowledge to the players. Also, at about this time, silver model soldiers were being used at the French Court to instruct the future king, Louis XIV, in the art of war” – David Nash (Wargames – 1974).
Periods are the “Eras” or “Level of Technology” present for wargaming. Having a Greek Army of 300 BC facing a Russian Army of 1944 AD is obviously quite a mismatch and both armies need quite different sets of rules to control how they perform. Hence we have “Periods” in which armies all operated in similar ways, or with similar weapons, and can be ‘played’ using a common set of rules.