When we check the books of seerah and sunnah we may be astonished that such a characteristic part of a mosque like a minaret was not yet known at the time of the prophet () as we may read in Sunan abi Dawod:
Narrated A woman from Banu an-Najjar:
Urwah ibn az-Zubayr reported on the authority of a woman from Banu an-Najjar. She said: My house was the loftiest of all the houses around the mosque (of the Prophet at Medina). Bilal used to make a call to the morning prayer from it. He would come there before the break of dawn and wait for it. When he saw it, he would yawn and say: O Allah, I praise you and seek Your assistance for the Quraysh so that they might establish Thine religion. He then would make the call to prayer.
She (the narrator) said: By Allah, I do not know whether he ever left saying these words on any night.
According the known historian ibn Ishaaq who reported this hadith and others in his maghazi (seerah) book at this time the mu'adhins used to chose the highest buildings to perform adhan from their top so a minaret didn't exist and according others this even was the case during the time of the 4 rashidi caliphs.
My question is who was the first to introduce minarets as the place from where the mu'adhin calls for the prayer and where or in which mosque?