'Centralization' law and 'Tribal Organization' law (for tribal rulers).All previous laws unlocked by independent county rulers.Laws Panel: An independent duke-rank liege may change the following legislation:.Enables use of crown focus (requires The Reaper's Due Expansion): An independent (or powerful vassal) duke-tier character may improve a province of their demesne by increasing its prosperity yearly gain and triggering events.Grand duke title: If the duke-tier character holds two or more duchies, they earn +1 demesne limit.'Emergency' usurp: If a Duke+ would become unlanded after losing a war, and a vassal controls a de jure county, they'll usurp the county from the vassal.Activates passive generation of technology points for non-nomads.Capital duchy bonus: All holdings directly owned by the duke-tier character, inside every de jure province located in the capital duchy (excluding the capital county itself), recieve +25% levy bonus if the duke (or equivalent) is independent, or +15% if the duke is a vassal.Capital county bonus: All holdings directly owned by the duke-tier character within the capital county recieve +50% levy bonus if the ruler is independent.The Republic DLC is required to play as a merchant republic. Granting a duchy to a burgher whose capital is coastal, will create a vassal merchant republic. Rulers of mercenary companies and holy orders are also considered to be of duke level, as are all religious heads except the Papacy and the Ecumenical Patriarchate.ДЄ duchy is the highest-ranked title that may be granted to a ruler of a different government type. There are also many titular duchies, including most of the Pagan tribes of the Baltic region. This normally costs 200 wealth, but is doubled for titular titles, and gradually halved as piety (or equivalent) approaches 1000. The portrait of dukes (or equivalent) has a thin silver border adorned by gems.Дe jure duchies may be created or usurped by a ruler who controls at least 51% of their de jure territory. It is generally held by a Duke tier character.

A Duchy in Crusader Kings II, is the level of authority ('title tier') below kingdom and above county.

Ck2 custom map