Kosem was a very controversial Sultana. What was her real character?? I couldn't find that what was her position during Murad IV's reign?? Some said that she introduced men to Murad so that he isn't influenced by ladies and wives. Is it true?? What was her role in Ibrahim's reign?? How exactly was she greedy for power from capturing Ibrahim and Mehmed's reign that Turhan became her enemy?? Did her greed ended her life?? or it was a political war that chose one?
Was she particularly controversial though? Kösem was appreciated by her contemporaries. Venetian ambassadors all described her quite positively, even when she was just a consort. What is always highlighted, I have noticed, is her prudence and wisdom:
Contarini noted, however, that Kosem "restrains herself with great wisdom from speaking [to the sultan too frequently of serious matters and affairs of state." Her circumspection was probably aimed at avoiding the displeasure of the sultan, who was determined to avoid giving the appearance of being dominated by a woman, as his father had been. — Leslie P. Peirce. The Imperial Harem: Women and Sovereignty in the Ottoman Empire
"[A]ll power and authority [is with] the mother, a woman completely different from that of Sultan Mustafa. in the prime of life and of lofty mind and spirit, [who] often took part in the government during the reign of her husband. — Leslie P. Peirce. The Imperial Harem: Women and Sovereignty in the Ottoman Empire
But because under the rule of [Kösem's sons] the major events of the Ottoman House happened, in which she knew how to preserve herself with esteem and honour, it must be said that she is a woman of good conduct, who knows very well how to join her private pleasures with public labour. — Le relazioni degli Stati europei lette al Senato dagli ambasciatori veneti nel secolo decimosettimo, raccolte ed annotate da Nicolò Barozzi e Guglielmo Berchet
This lady is Greek, around forty-five of age at present, of beautiful appearance and very noble features, of gentle nature, she delights in pleasure and solace, she is virtuous, wise, prudent, splendid and generous — Luigi Firpo, Relazioni di ambasciatori veneti al Senato: Constantinopoli relazioni inedite (1512-1789)
This is how Özlem Kumrular describes her in her book Kösem Sultan: iktidar, hırs, entrika
A resolute woman who managed to survive half a century in the Ottoman capital and who left her name on the pages of history. Described by various epithets: Sultana Kösem, tyrant, regent, intelligent, patient, capable of fighting for power at any cost. Also a woman who knows when to wait and when to act. Guided by reason, not temporary moods, able to open any door. She is a white-headed woman, whom history does not adore as an extraordinary beauty, but that remembers her for her charm, and above all her intelligence and cleverness. [...] In European sources, she is one of the women who gained immortality due to her image as regina (queen) and regina madre (queen mother). It was Kösem Sultan, also called imperatorice (empress), who tried to protect the state from collapse in the most turbulent period of Ottoman rule. At the same time, in the name of power, of this specific relationship that links the institution of the state with her own love, she sacrificed her own sons, her own blood. [...] Moreover, Kösem strengthened a state whose near collapse had already been talked about, even though it seemed far away to most in this turbulent period.
I don't understand what you mean by position in Murad IV's reign. She was first regent of the sultanate and then just valide sultan. After she left the regency, Venetian ambassador Alvise Contarini said that:
In the time I was in Istanbul [1636-1640], she only aimed to curb her son Sultan Murad's violent temperament.
In the present government, to the extent that this son's capabilities are less, she is held in greater esteem [than at the end of Murad's reign]. And thus, with her commanding affairs within the palace and the grand vezir [commanding] those outside, it happens quite often that these two rulers conic up against each other and in doing so take offense at each other, so that one can say that in appearance they are in accord but secretly each is trying to bring about the downfall of the other. (translation by Leslie Peirce)
I have already talked about this but that she supplied boys to Murad IV to keep him from getting influential consorts is a myth that has somehow entered Ottoman historiography. Murad IV had - according to Evliya Celebi - 32 children so he certainly had consorts. That they weren't influential is because of Kösem's overbearing presence as regent first and valide sultan after.
Again, I have talked about this countless times: she did not steal Turhan's position during Mehmed IV's reign and during Ibrahim's people were almost relieved that she was again ruling behind the scenes because Ibrahim was not good at ruling. On Ibrahim's deposition, Kösem was offered the regency because Turhan was too young:
According to Karaçele-bizade Abdu laziz Efendi, then the chief justice of Rumeli and a central figure in the dynastic upheavals of the time, it was considered prudent to appoint the more experienced woman regent in contravention of tradition: It being an ancient custom that upon the accession of a new sultan the mother of the previous sultan remove to the Old Palace and thus give up her honored office, the elder valide requested permission to retire to a life of seclusion. But because the loving mother of the [new] sultan was still young and truly ignorant of the state of the world, it was thought that it she were in control of government, there would result the possibility of harm to the welfare of the state. Therefore the elder valide was reappointed for a while longer to the duty of training and guardianship, and it was considered appropriate to renew the assignment of crown lands to the valide sultan. — Leslie P. Peirce. The Imperial Harem: Women and Sovereignty in the Ottoman Empire
