Plone is free and open source content management system (CMS) written in Python. It is built on top of the Zope application server. Its strengths are in intranets, websites and document management. It has robust support for multilingual content, versioning and is easy to use.
The project has been actively developed since 2001, is available in more than 40 languages, and has the best security track record of any major CMS.
It is owned by the Plone Foundation, a not-for-profit organization that owns the code and trademarks.