I’ve been reading Simon S. Montefiore’s “Stalin The Court of the Red Tsar” p. 424
"Later, Stalin humiliatingly emptied his pipe on Khrushchev’s head: “That’s in accordance with Roman tradition,” he said. “When a Roman commander lost a battle, he poured ashes on his own head… the greatest disgrace a commander could endure.”
I haven’t been able to find any reference to this Roman tradition of defeated Roman generals pouring ashes over their heads. Did this tradition begin with the Romans or does it go back further? I look forward to your feedback.