WSDL 1.0 was the first release of WSDL, released in September of 2000. It contained all of the major concepts that remain in WSDL. WSDL 1.1 superceded it. For the most part, WSDL 1.0 is rarely used anymore.

Here is the WSDL 1.0 specification.

See: WSDL, WSDL 1.1, WSDL 1.2