This article contains a list of the oldest existing social institutions in continuous operation, by year of foundation, in the world. Inclusion in this list is determined by the date at which the entity met the traditional definition of an institution – may it be public, political, religious or educational – although it may have existed as a different kind of institution before that time. This definition limits the term "institution" to organisations with distinctive structural and legal features. It must also be still in operation, with continuity retained throughout its history, and so some institutions which were abolished at some point are excluded, despite resurrections (although these may be dealt with further down in this article). Some institutions re-emerge but with new foundations, and these too are omitted from the regular list.