[7][8] However, the reports of foreign ambassadors suggest that Ahmed actually liked his half-brother: he had been on good terms with his older half-brother Şehzade Mahmud (full brother of Mustafa, executed by his father Mehmed III and his grandmother Safiye Sultan) and was shocked by his death, and also felt sympathy for Mustafa's very young age.

[6] A court faction headed by the Şeyhülislam Esad Efendi and Sofu Mehmed Pasha (who represented the Grand Vizier when he was away from Constantinople) decided to enthrone Mustafa instead of Ahmed's son Osman.

It was hoped that regular social contact would improve Mustafa's mental health, but his behavior remained eccentric.

The Ottoman historian İbrahim Peçevi wrote "this situation was seen by all men of state and the people, and they understood that he was mentally disturbed.

After a Janissary rebellion led to the deposition and assassination of Osman II in 1622, Mustafa was restored to the throne and held it for another year.

One of the dispatches of Baron de Sancy, the French ambassador, "suggested that Mustafa was interested in leading the Safavid campaign himself and was entertaining the idea of wintering in Konya for that purpose.

[18] His mental condition unimproved, Mustafa was a puppet controlled by his mother and brother-in-law, the grand vizier Kara Davud Pasha.

He believed that Osman II was still alive and was seen searching for him throughout the palace, knocking on doors and crying out to his nephew to relieve him from the burden of sovereignty.

[19] "The present emperor being a fool" (according to English Ambassador Sir Thomas Roe), he was compared unfavorably with his predecessor.

The regime tried to end the conflict by executing Kara Davud Pasha, but Abaza Mehmed continued his advance.

Another source states that he was executed by the orders of Sultan Murad IV, who was on his death bed, and rumors say that he wanted to end the lineage.