High-treason synonyms

On the 24th of November he was indicted for high treason at the Old Bailey, the chief ground being a paper of association for the defence of the Protestant religion, which, though among his papers, was not in his handwriting; but the grand jury ignored the bill.

You're talking about high treason at the VP level at least to access those things.

They were pronounced by the Council of Blood to be guilty of high treason (June 2, 1568).

On the 19th of January 1648 Cromwell was accused of high treason by Lilburne.

In particular, his acceptance of the crown would have guaranteed his followers, under the act of Henry VII., from liability in the future to the charge of high treason for having given allegiance to himself as a de facto king.