The Ruling Council of Twenty-Three was a centuries old, secret brotherhood intent on world domination through the use of low profile manipulations and maneuvering agents into positions for when they were ready to take control. The group was also interested in acquiring several artifacts Indiana Jones had encountered in his lifetime: the Omphalos, the Sankara Stones, the Ark of the Covenant, and the Holy Grail.
Jones had unknowingly become a target of the Council of Twenty-Three when actions taken by the archaeologist had disrupted their work more than once, including his success in stopping Enterprise Ventures International, Limited, one of the Council's client organizations. In 1939, they issued a letter from Zurich, Switzerland declaring Jones was to be stopped, and directed agents to look into three incidents they had dubbed Indiana Jones and the Peril at Delphi, Indiana Jones and the Unicorn's Legacy and Indiana Jones and the Sky Pirates as research for the task.