Abstract. Time is omnipresent on the (Semantic) Web. However, formalism like XML, XML Schema, RDF, OWL and (Semantic) Web query languages have, if any, only very limited notions of temporal data types and temporal theories built-in. Recently, the development of Web Services for temporal operations has begun. In this article, we describe a connection, possibly the first one, between such Web Services and Web formalisms: A proposal of a type system for temporal and calendric data, called multi-calendar temporal type system seamlessly integrated into a host (query) language. The type system’s associated type checking methods are beyond the scope of this article. For proof-of-concept purposes, the Web and Semantic Web query language Xcerpt has been chosen.