When did the weeping on Imam Hussein (PBUH) start?

Answer

In the name of Allah, the first of those who wept was the Great Prophet (PBUH&HF) for what Allah Almighty revealed to him about what will be going on in the martyrdom of the Imam Hussein (PBUH). Apparently, some narrations attain that every prophet of the former prophets wept after Allah revealed to him what will be happening on the grandson (Imam Hussein) of the Prophet (PBUH&HF).