Minimum Requirements

PC:
Operating system: XP/Vista/Windows7
Processor: Intel® Pentium® IV 2.4 GHz or AMD 3500
Memory: 2 Gb RAM
Hard disk space: 2 GB Available HDD Space
Video: NVIDIA® GeForce 8800 or ATI Radeon® X1900, 512mb graphics memory required.
Resolution at least: 1024*768
Sound: Direct X-compatible sound card
DirectX®: DirectX 9

Controller support: 3-button mouse, keyboard and speakers
Special multiplayer requirements: Internet Connection for multiplayer

Mac:
Operating system: Mac OS X 10.6.8 or later
Processor: Intel Core Duo Processor (2GHz or better)
Memory: 2 GB RAM
Hard Disk Space: 2 GB
Video Card: ATI Radeon HD 6750 / NVIDIA GeForce 320 / NVIDIA GeForce
9600 or higher
Peripherals: Mouse, keyboard

Linux:
Operating system: Ubuntu 12.04 LTS
Processor: Intel Pentium 2.4 GHz or AMD 3500
Memory: 2 GB RAM
Hard Disk Space: 2 GB
Video Card: ATI Radeon HD 6750 / NVIDIA GeForce 320 / NVIDIA GeForce
9600 or higher; 1024MB graphics memory required
Peripherals: Mouse, keyboard

Requires the base game Crusader Kings II to play.