Property:Date
[http://www.nga.gov/content/ngaweb/research/casva/research-projects.html A Project of the National Gallery of Art, Center for Advanced Study in the Visual Arts ]
"Date" is a type and predefined property provided by Semantic MediaWiki to represent date values. This property is pre-deployed (also known as special property) and comes with additional administrative privileges but can be used just like any other user-defined property.