Joseph Marie Noel Valois, 1911 Encyclopædia Britannica, Volume 15… (1911)
“ The news of the pope’s escape was received at Constance with an extraordinary outburst of rage, and led to the subversive decrees of the 4th and 5th sessions, which proclaimed the superiority of the council over the pope. Duke Frederick of Austria had hitherto sheltered John’s flight; but, laid under the ban of the empire, attacked by powerful armies, and feeling that he was courting ruin, he preferred to give up the pontiff who had trusted to him. ”
