An alliance is a player-formed organization that shares treasury, council voting, joint wonders, and binding diplomatic contracts. Alliances are the unit of political action in the late game — most victory paths require alliance coordination.
- Forming — any player can found an alliance from the alliance panel. Cost: a small founding stake (resources + reputation).
- Joining — application + existing-member vote (typically simple majority).
- Membership cap — culture and tech-gated. Typical caps are 8–16 active players.
- Leaving — drop a small reputation hit; lose claim on shared treasury.
Each alliance has a shared treasury — a resource pool members contribute to:
- Voluntary contributions from per-player pools.
- Auto-contribution percentage (member-set, default 5–15%).
- Treasury caps based on tech and member count.
Treasury funds:
- Joint wonder construction.
- Alliance-wide military campaigns (mass recruitment, supply).
- Diplomatic contracts (some require treasury draw).
- Member emergency relief (famine, war).
Alliance members can sponsor each other:
- A wealthy member can fund a needy member's specific project (tech, building, wonder share).
- Sponsorship is logged for reputation; freeloaders are visible.
- Used as a soft governance lever — the most-sponsoring members tend to dominate council votes.
Most alliance-level decisions go through the council:
| Vote type |
Threshold |
Notes |
| War declaration |
Simple majority |
Members opposed can veto with reputation cost. |
| Treaty signing |
Simple majority |
Single proposer + counter-offer process. |
| Membership change |
Simple majority |
Add or remove a member. |
| Concordance Charter |
Supermajority (~2/3) |
Highest commitment level. |
| Wonder priority |
Simple majority |
Which wonder to build next. |
| Treasury allocation |
Member-stake-weighted |
Heavy contributors get heavier vote. |
Vote results are server-binding. A defeated member can leave, but the decision sticks.
Joint wonders fund-raised by the alliance:
- Built in any member's Greatcity (1 wonder slot per Greatcity, 2 per Capital).
- All members can contribute resources.
- Defended jointly when sieged.
- Counts toward the Wonder Victory.
Most viable victory paths require 5 alliance wonders (Wonder Victory) or 1+ wonder per peace signatory (Concordance compatibility).
See diplomacy for the full 11-contract catalog. Highlights for alliance leaders:
- Non-Aggression Pact — mandatory baseline for stable neighbors.
- Mutual Defense Pact — drag-into-war risk; useful for backbone allies.
- Joint Wonder — costs reduced when split across alliances.
- Concordance Charter — the peace-victory binding contract.
Unique events fire only at alliance scale:
- Alliance Wonder completion — global event, faith / morale boost across members.
- Alliance Council Crisis — when a member triggers civil war or a major betrayal.
- Alliance War Declaration — public escalation event, broadcasts to all players.
- Alliance Concordance Sign — published peace event; pressure on rival alliances.
Confederations are a related but distinct mechanic — see confederations. In short:
- Alliance = any group of players agreeing to mutual support.
- Confederation = a subset of alliances that share culture + geography, gaining additional passive bonuses (Drum-Speed, Adoption Network, Elevation Logistics, etc. — culture-specific).
A culture-pure alliance often forms a confederation automatically.
- Form an alliance early. Even a small one, with a single ally, is better than going solo.
- Don't over-tax member contributions. 5-10% works; 25%+ drives members away.
- Document the wonder priority. Coordination beats individual heroics.
- Mid-game pivot from many small alliances to fewer larger ones. Consolidation enables bigger wonders and Concordance.
Sources: alliance.md (20K), alliance_workspace.md (40K background notes), rts_alliance_system_design_table.xlsx, diplomacy_system.md.