What is the name of the treaty that created the European patent system?

The treaty that created the European patent system is the European Patent Convention.

The EPC was signed in Munich on 5 October 1973 by European states seeking a shared procedure for granting patents. It established the European Patent Organisation and its operating authority, the European Patent Office. The convention created a common legal framework so applicants could pursue patent protection through one centralized application and examination system.

The EPC entered into force in 1977. A European patent is not automatically a single patent with identical enforcement everywhere; after grant, it generally takes effect in the contracting states selected by the applicant, subject to the convention’s rules and national procedures. Later developments, including the Unitary Patent system, build on but do not replace the EPC framework.

The alternatives are related international agreements but serve different purposes. The Patent Cooperation Treaty simplifies international filing, TRIPS sets minimum intellectual-property standards, and the Paris Convention establishes broad principles such as priority rights.