Knowledge is a vital ingredient in Rise of Kings 2, and can be accumulated in several ways:
- Building universities and staffing them with scholars, or
- Trade: the amount of knowledge you receive is based on Science Level +1 / Religion level + 1. For Melaka, it is 2.5 (sci level +1 / rel level +1)
- (Barbarians only) Killing enemies. The amount of knowledge you receive from killing enemy units is based on Commerce level + 1 - Religion level.
Knowledge is a vital resource, and is used primarily to research trunk technologies (religion, commerce and science). Once Chemistry (a science level) is discovered, then it is also used in ever increasing amounts to create gunpowder units. Knowledge is an important resource, especially in the construction of advanced naval units. Wonders also require knowledge for upgrading. The following factions are classified as "barbarians", and thus are reliant on raiding and trading to accumulate knowledge.
- Kandy - political research increases knowledge gains from warfare.
- Bagan - no penalty from religious research on knowledge gains from warfare.
- Melaka - Added knowledge from trading
- Inca - no penalty from religious research on knowledge gains from trading
- Cherokee - Cherokee caravans generate knowledge for factions that visit them, but elicit more for their masters