Rise of Mankind: A New Dawn is a new sequel of the great Civilization IV: Beyond the Sword game. A New Dawn serves as a new expansion, adding a huge and balanced new technology tree, putting emphasis on new buildings, new units and new technologies. Based on the incredibly popular former mod Rise of Mankind, A New Dawn transforms Civilization IV, reaching to new heights and giving the players the best Civilization experience of all time. It contains a powerful and vastly superior new AI, charismatic new leaders and a new revolt and revolutions system. The huge amounts of new content also includes an advanced and reworked diplomacy system, a myriad of new automation options, an adaptive difficulty, and many other enhancements.
This is the latest full installer from June 2015 (rev978). It contains a launcher and a updater. You'll only need to download this once if you update the game. It is compatible with the Windows version of the game only, but it's known to work under Linux (with Wine) and MacOS (Crossover/Wine).