Orbis Terrarum

ORBIS TERRARUM – A Historical Total Overhaul
Bringing EU4 as Close to EU5 as Possible

This mod is in active development. Version 1.0.2 is feature-complete but not fully playtested. Expect bugs, balance issues, and rough edges. Your feedback is the most valuable thing you can offer.

WHAT IS ORBIS TERRARUM?

A comprehensive total overhaul built around one principle: no shallow content. Every system adds historical depth and mechanical weight. This is not a numbers-tweaking mod. It changes how the game plays.

CORE SYSTEMS

Empire Lifecycle
Nations progress through Rising, Peak, Stagnation, and Decline. Each phase carries modifiers and shapes your reign. The 17th Century General Crisis is built into the system. Ignore the reform window during Stagnation and Decline becomes inevitable.

Development Revolution
Manual development costs are multiplied roughly 9-10x. Clicking provinces to prosperity is no longer viable. Provinces grow organically through terrain, trade routes, buildings, and events. Farmland provinces gain one development every 15-20 years. Mountains barely grow at all. Building a great empire takes generations.

4,826+ Events
Climate cycles, epidemics, dynastic crises, military campaigns, economic shocks, cultural movements, religious tensions, and historical pivot moments. The Franco-Ottoman Alliance. The Polish relief at Vienna. The Habsburg inbreeding crisis. Century chains covering the 15th through 18th centuries.

Ottoman Overhaul
Four unique estates: Sipahi, Janissary Corps, Ulema, Levantine Merchants. 140 estate privileges. A Caliphate system that reshapes Sunni diplomacy. The Beylik subject type with upgrade paths. Devshirme mechanics tied to Christian population. Celali revolts. 35 Ottoman flavor events.

Diplomatic Overhaul
42 unique subject types across 6 tiers: feudal vassals, protectorates, tribute systems, colonial variants, trade companies, and special types like the Ragusa dual-tributary model, Chinese tributary, Khanate dependency, Free Port, and Banking State. 40 new peace terms including army disarmament, enforced marriage, dynasty delegitimization, and technology transfer. 20 new diplomatic actions including ultimatums, economic coercion, and the Ottoman Capitulation system. A full ultimatum and diplomatic crisis escalation system. 448 diplomatic events.

Trade Company Evolution
Trading Posts evolve through four phases into Company Dominions. The VOC has unique Dutch mechanics with dividend events and a 1799 bankruptcy chain. The EIC consolidates multiple posts into a single company and eventually transfers to Crown rule. The French Compagnie des Indes faces EIC rivalry. Companies do not consume diplomatic relation slots and can fight their own wars.

284 Missions
Custom mission trees for 12 major powers: Ottoman Empire, France, England, Habsburg, Russia, Portugal, Spain, Venice, Mughal Empire, Ming China, Japan, and Poland. Missions are hidden when the relevant DLC is present. DLC missions take priority.

8 Military Doctrines
Janissary, Tercio, Steppe, Linear, Hussite, Mughal, Naval Supremacy, Swiss. Each changes how your nation fights.

30 New Idea Groups and 199 Policies
A complete overhaul of the idea system across Administrative, Diplomatic, and Military categories.

24 Living Faiths
Every major religion has permanent passive modifiers. Lutheran vs Calvinist identity. Third Rome progression. The Caliphate-Papacy rivalry.

Population Tracking
Province-level population variables interact with plagues, famines, revolts, and growth events. 100 events and 3 disasters built on this system.

50+ New Buildings
Across military, economic, religious, administrative, and naval categories.

79 New Advisor Types
A complete expansion of the advisor system with historically themed advisors across all categories.

Consort Power
Consorts now provide monarch power bonuses based on their stats. A small but meaningful addition to dynastic gameplay.

582 Updated Flags
Improved flag artwork for hundreds of nations.

NUMBERS

4,826 events, 105 namespaces
42 subject types
40 peace terms
284 missions across 12 major powers
38 disasters
30 idea groups, 199 policies
8 military doctrines
20 diplomatic actions, 6 CB types
79 advisor types
582 updated flags

DEVELOPMENT STATUS

This is version 1.0.2.

Balance is not final. Modifier values and event timings have not been tuned through extensive campaigns. The map is vanilla. A province overhaul is planned but not yet implemented. AI behavior with custom systems is untested. Some content was generated at scale with AI assistance, which means occasional historical inaccuracies or logical inconsistencies may appear.

CHANGELOG

v1.0.2
Fixed critical bug where diplomatic, economic, warfare, and development decision files were placed in the wrong directory and were never loading in-game. All Orbis Terrarum decisions are now active for the first time.

v1.0.1
Event pacing fixed: events now fire roughly 8-10 times per year per country instead of dozens at once. Scope errors fixed across trade and epidemic event chains. Mission trees now correctly hide when DLC is present. Belgrade event prerequisite logic corrected. Loading screen updated.

HOW TO REPORT ISSUES

Bug reports: tell us what happened, which country and year you were in, and the event ID if visible (example: OT_trade_dynamics.14).

Logical or historical errors: tell us when an event fires in the wrong order, a mission has a backwards prerequisite, or a description contradicts its effects.

Suggestions: missing events, shallow mechanics, balance feedback after longer campaigns.

All reports are read and acted on.

COMPATIBILITY

EU4 version: 1.37
No DLC required. Mission trees activate only when relevant DLC is absent.
English only. Ironman: no. Multiplayer: untested.
Not designed for use alongside other overhaul mods.

KNOWN ISSUES

Trade company UI may not display correctly in all configurations.

Thank you for trying Orbis Terrarum. This mod exists because someone wanted EU4 to feel like EU5.