Summaryd20 Past is a helpful supplement to the d20 Modern role-playing game, however it is very limited with items, weapons, and wealth conversions with the past to present, but it does provides rules andframework for campaigns/games set in a wide variety of historic settings from the Renaissance to Mid Cold War. In d20 Past the authors cover five centuries of technology, spanning from 1450 through 1950. However here will be meant to expand upon where the authors left off in d20 Past, giving more items, weapons, gadgets, and other helpful rules and guidelines, that GMs do not have to usebut are helpful.
Progress LevelsProgress Levels (PL) are d20 use of arbitrary measurements to determine how advanced a culture is, based on their developments in technology, society, and other factors. This concept was first introduced in d20 Future supplement, to describe both the level of technology in the campaign as well as the technology levels of other species comparative to the human one. Progress levels of six and higher were studied in d20 Future, with the default d20 Modern setting encompassing progress level five. In d20 Past, two progress levels are studied; Progress level three (the age of reason) and progress level four (the industrial revolution). This is where this page and supplementary pages will help with the Technology of these time periods.
PROGRESS LEVELSA Progress Level (PL) is an indication of the state of technology that exists in a particular society or civilization (which, in a science fiction setting, may be located on a planet other than Earth). This state of technological development generally pervades all aspects of a culture, particularly at higher levels (PL 5 and beyond) when long-range communication is virtually instantaneous. Even at lower levels, it’s unlikely—but not impossible—for a group of humans (or other sentient beings) to be at one Progress Level in some respects and at another one in other respects.Progress Level may vary wildly from place to place on the same world or even the same continent.
Also See the d20 Past Equipment Page: Here