Founding Members of the EU: Belgium, Italy, Luxembourg, Netherlands Joined in 1957

Belgium, Italy, Luxembourg, and the Netherlands were founding members of the European Economic Community (EEC)—the EU's predecessor—established by the Treaty of Rome.

Accession Date

25 March 1957 — Treaty of Rome signed
1 January 1958 — Treaty entered into force

The Six Founding Members

Context

• Preceded by European Coal and Steel Community (ECSC, 1951) — same six countries
• Treaty of Rome created EEC (common market) and Euratom (nuclear cooperation)
• EU formally established by Maastricht Treaty (1993) — these six were automatic members

Why These Six?

• Post-WWII reconciliation (France–Germany core)
• Economic complementarity (coal, steel, industry, agriculture, ports)
• Political will for supranational integration (Monnet, Schuman, Adenauer, De Gasperi, Spaak, Bech)

Belgium, Italy, Luxembourg, and the Netherlands have been in the European project from day one—over 65 years of continuous membership.