The Government of Canada Core Subject Thesaurus has its origins in the Subject Thesaurus of the Depository Services Program at Public Works and Government Services Canada. The Subject Thesaurus of the Depository Services Program was developed between May 1999 and February 2000 as a source of indexing terms for the Government of Canada Publications Database. In 2001, various projects for indexing information resources of the Government of Canada lead to the creation of the CST, by enlarging the scope of the Subject Thesaurus. Between 2001 and 2004, the Subject Thesaurus of the Depository Services Program was derived from the CST. In June 2006, Library and Archives Canada took over the responsibility of managing and updating the CST from the Depository Services Program. Both tools now evolve as distinct products.