Jaswant Singh Chail, 20, who has been charged under Britain's Treason Act, is accused of making a threat to kill the 96-year-old monarch, possessing a loaded crossbow with intent to use it to injure the queen, and possession of an offensive weapon.
Elizabeth, who died last month, was at the castle on the day of the intrusion with her son and now King Charles and other close family members
Chail, who appeared at Wednesday's hearing via videolink wearing a black hoodie, spoke only to confirm his name and his date of birth.
He was told the trial date was set to March 20 next and would last two to three weeks.
He did not enter a plea, the case was adjourned for further evidence to be obtained and Chail was detained in custody. The next hearing will take place at a date yet to be confirmed in December.
(Reporting by Michael Holden; editing by William James)
