BIRON, Charles de Gontault, created duke of Biron by Henri IV., was a man of great intrepidity, but fickle and treacherous. In 1601 he was sent as ambassador to the court of Queen Elizabeth to announce his royal master's marriage with Mary of Medici; but being discovered in a treasonable correspondence with Spain, he was beheaded in the Bastille at Paris, July 31, 1602.