Building & Development
The prosperity and military might of your realm in Crusader Kings III are directly tied to the development of your holdings. Each county you control has a limited number of building slots, and the choices you make here will shape your economy, your levies, and your ability to wage war. Holdings are divided into three main types: Castles, Cities, and Temples. Each type offers unique building trees and benefits.
Castles
Castles are the backbone of your military. They primarily focus on increasing your levy size and providing defensive bonuses. Early game castles might focus on basic barracks to bolster your troops, while later game options can include specialized units like Men-at-Arms, which are professional soldiers that provide significant combat advantages. Investing in castle buildings is crucial for any ruler looking to expand their territory or defend against aggressive neighbors.
Cities
Cities are your economic powerhouses. They generate significant amounts of gold, which is essential for everything from maintaining your armies to bribing vassals. City buildings often focus on increasing tax income, trade revenue, and development. While they don't directly contribute to your levy size, the gold they provide allows you to hire mercenaries or maintain larger Men-at-Arms companies, indirectly boosting your military strength.
Temples
Temples, controlled by religious leaders, offer a different set of benefits. They primarily generate piety, which is used for religious actions like excommunicating rivals or fabricating claims. Temples can also provide modest gold income and, in some cases, levy contributions. The specific benefits of temple buildings can vary depending on your ruler's faith and its doctrines.
Development
Beyond specific buildings, each county has a "Development" level. This represents the overall prosperity and infrastructure of the region. Higher development levels increase tax income, levy size, and unlock more advanced building options. You can increase development by constructing specific buildings and through certain events. Prioritizing development in your core demesne is a sound strategy for long-term success.