The envoy Mestrianus returned to Licinius's camp bearing Constantine's impossible terms. When the demands were read aloud—the surrender of all European provinces, the execution of his newly-appointed Caesar Valens—Licinius did not fly into a rage. Instead, a deathly, cold calm settled over him. He had been a soldier on the brutal Danube frontier for thirty years; he understood an ultimatum when he heard one. Constantine was not offering peace; he was demanding a surrender so total it was indistinguishable from annihilation.