The 1988 IAU (International Astronomical Union) General Assembly meeting in Baltimore, USA, adopted the following resolution:

 RESOLUTION B2: Working Group on FITS
      The XXth General Assembly of the International Astronomical Union,
      considering
             the high importance of the Flexible Image Transport System (FITS)
             for the exchange of digital data between astronomical institutes
             and for astronomical archives;
      decides
             to form a Working Group on FITS to maintain the existing FITS
             standards and to review, approve and maintain future extensions
             to FITS, recommended practices for FITS implementations, and the 
             thesaurus of approve FITS keywords.

The FITS Working Group was formed under IAU Commission 5, Documentation and Astronomical Data.

Reference: Transactions of the International Astronomical Union (1988), Vol. XXB, p 52.