The European Commonwealth was once a federal union. It is, however, unknown which European states were members.
In 2052 (1240), Europe was heavily dependent on oil imports from the petroleum-rich states of the Middle East and responded with military action to rapidly rising oil prices that were damaging its economy, starting the terrible global conflicts that later historians simply lumped together as the Resource Wars.
The outcome of the conflict suggests that the European Commonwealth possessed a unified military. It is unknown whether the Commonwealth took steps to ensure its survival like the United States did.
When the European Commonwealth-Middle East War came to an end in 2060 (1248), the Commonwealth began to dissolve as many countries withdrew from the state. A long civil war followed, lasting for an unknown period of time.