A European application is accorded as its date of filing the date on which it satisfies the requirements of Art. 80, or, if filed under the PCT, the date on which it satisfies Art. 11 PCT. This date remains unchanged except in the special circumstances of late-filed drawings provided for in Art. 91(6) EPC and Art. 14(2) PCT.

The date of filing may be the only effective date of the application. It will be of importance for fixing the expiry of certain time limits (e.g. the date by which the designation of the inventor must be filed under Art. 91(5)), for determining the state of the art relevant to the novelty or obviousness of the subject-matter of the application, and for determining, in accordance with Art. 60(2), which of two or more European applications from separate persons for the same invention is to proceed to grant.