Mirza Mohammad Sadegh Marvazi, a historian of Qajar period,was from Shahjahanmarv. At first, Mirza Mohammad Sadegh was positioned as a secretary in Fath-Ali Shah court and then as a historiographer, who composed poems and adopted "Homa" as a pen name for himself. In a short time, he attained suitable positions, there after he was sent to several domestick and abroad missions by Fath-Ali Shah and Abbas Mirza.Since,historiographer was among few persons who wrote letters to Ghaem Magham and consulted with Ghaem Magham and Abbas Mirza, he was aware of court affairs and in some of his works, he has revealed the court secrets and events directly and indirectly.His available works include Sheyam-e-Abbasi, Zinat-al-madayeh, Divan (complete poetical works) of Homa Marvazi,Tohfeye Abbasi, Rahat-al-arvah, Story of Mirza Sadegh, Majma-al-asrar, debate beween intelect and fortune, portrait of Fath-Ali Shah Qajar, and history of Jahan-Ara. Among these, "History of Jahan Ara" is probably his best work.This article tries to look at cultural, scientific and political life of Mirza Sadegh Marvazi using the "history of Jahan Ara,-2nd volume".