History of the English People, Volume 3

"Once safe in the Tower, it was easy to wrest from Richard a resignation of his crown; and this resignation was solemnly accepted by the Parliament which met at the close of September 1399. But the resignation was confirmed by a solemn Act of Deposition. The coronation oath was read, and a long impeachment which stated the breach of the promises made in it was followed by a solemn vote of both Houses which removed Richard from the state and authority of king."