Napoleonic Era is a revolutionary, non-commercial and fan-based modification for Ensemble Studios' latest RTS game, Age of Empires III. It is currently the most thorough and anticipated mod of Age of Empires III ever made.

The mod was originally created by game modder and Age of Empires gamer Alexander Flegler (Xastor), inspired by the idea of adding a Swiss civilization suggested by his friend Jahn Hummel (Twister3). Napoleonic Era soon grew from this and was discussed frequently on the forums of Age of Empires III Heaven. After release v0.2, a very interested member of these forums, Fernando Barbosa (Walker), discussed many ideas to improve and balance the game and was soon made balance lead.

A while after the release of v0.8, Matthew Sher worked with modder Xentelian to complete the Unit Upgrades Modpack. Seeing Matthew's texture work, Kastor successfully requested him to become Napoleonic Era's graphics lead. David Rosehnal, having planned to make a campaign about the Napoleonic Era, has made and maintained the old NE website. After the hack Michael M. (michfrm) has taken his place and created the new NE website with a new design. Peter Piepenburg (Tilanus Commodor), a historically interested forumer, has been actively involved in the creation of Napoleonic Era with several valuable constributions. Furthermore the team reserved themselves the right to sign up new specialized members to improve specific aspects of the mod. The Napoleonic Era Team can be divided in two classes: Core Team and Assistants.

The Napoleonic Wars were chosen for the game's general theme due to the fact that these were the most influential military events during the time period of Age of Empires III, next to its current theme, the colonization of America.

Napoleonic Era features a great deal of new gameplay elements, returning a few well-missed elements from Age of Empires II, like removing the limit of builders working on one building, improving the arsenal, and new abilities for Explorers. It includes eight completely new civilizations, the Italians, Prussians, Austrians, Americans, Swedes, Poles, Inca and Swiss. It also redesigns the existing French and German civilizations.

These civilizations are very different from each other, most receive a new AI personality, new technologies, new cards, and the new ones receive their own Homecity. All of the new civilizations and most of the existing ones get many new unique units, in addition to several new standard units. All these new units have had amazing care put into them to make them as distinctive, realistic and interesting as possible. Even new campaigns are part of the Napoleonic Era Mod. Furthermore the game incorporates usage of Matthew Sher's Unit Upgrades Modpack, so that the units from the original game upgrade in every age. To fit the new theme of the wars occurring in Europe, Napoleonic Era includes many new random maps, e.g. from Europe, America and even other places around the world, many of them consist completely new native allies like Finns or Greeks.