For the purposes of determining novelty, a prior document should be read as it would have been read by a person skilled in the art on its "relevant date". The relevant date of a previously published document is its publication date, and that of a document within the meaning of Art. 54(3) EPC its date of filing (or, as the case may be, priority date) (Guidelines G‑VI, 3 – November 2018 version).

Under Art. 54(2) EPC, the state of the art comprises everything made available to the public by means of a written or oral description, by use, or in any other way, before the filing or priority date of the European patent application.

An invention can be patented only if it is new. An invention is considered to be new if it does not form part of the state of the art. The purpose of Art. 54(1) EPC is to prevent the state of the art being patented again (T 12/81, OJ 1982, 296; T 198/84, OJ 1985, 209).