In which Hijri year was the Athaan legislated?
All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
The Athaan (i.e. call for prayer) was legislated and prescribed during the first year of the emigration to Al-Madeenah. Imaam An-Nawawi said in Al-Majmoo‘ Sharh Al-Muhathab, "‘Abdullaah ibn Zayd (i.e. Muhammad ibn ‘Abdullaah ibn Zayd ibn ‘Abd Rabbuh Al-Ansaari) witnessed the Pledge of Allegiance at Al-‘Aqabah and the Battle of Badr with the Prophet, sallallaahu ‘alayhi wa sallam. He saw a vision about the Athaan in the first Hijri year after the Prophet, sallallaahu ‘alayhi wa sallam, built his mosque in Al-Madeenah."Allaah Knows best.
You can search for fatwa through many choices