As Detailed

As detailed in the indictment, on September 23, 2021, the Select Committee issued a subpoena to Mr. Bannon.  The subpoena required him to appear and produce documents to the Select Committee, and to appear for a deposition before the Select Committee.  According to the indictment, Mr. Bannon refused to appear to give testimony as required by subpoena and refused to produce documents in compliance with a subpoena.

-- U.S. Attorney Matthew M. Graves for the District of Columbia, as quoted in a Justice Department press release, "Stephen K. Bannon Indicted for Contempt of Congress", 12 November 2021