d20 Past is a d20 based role-playing game released by Wizards of the Coast in 2005 as a supplement to d20 Modern, providing a framework and new rules for campaigns set any historic settings from the Renaissance to World War II, including new character options and rules for early modern firearms. It begins with an exploration of the historical period between around 1450 and 1950, then provides rules for creating characters and campaigns that blend realism and fantasy.