Instead, the sultan's grandmother and the previous Valide sultan, Kösem Sultan, was reinstated to this high position. Kösem Sultan was a Valide (mother) under two sons, thus having the more experience of the two women. However, Turhan turned out to be too ambitious a woman to lose such a high position without a fight. In her struggle to become Valide sultan, Turhan was supported by the chief black eunuch in her household and the grand vizier, while Kösem was supported by the Janissary Corps. Although, Kösem's position as Valide was seen as the best for the government, the people resented the influence of the Janissaries on the government. In this power struggle, Kösem planned to dethrone Mehmed and replace him with another young grandson. According to one historian, this switching had more to do with replacing an ambitious daughter-in-law with one who was more easily controlled. The plan was unsuccessful as it was reported to Turhan by Meleki Hatun, one of Kösem's slaves. As N.M. Penzer describes it: Whether Turhan sanctioned it or not, on the night of 2 September 1651, Kösem Sultan was murdered three years after becoming regent for her young grandson. As regent With the death of her rival, Turhan became the Valide Sultan. As a regent, Turhan wielded great power. She accompanied her son the sultan to important meetings and on several occasions spoke from behind her curtained sitting place. She was deeply loved and respected by her son, the sultan. Due to her inexperience, Turhan relied on other members of the government to advise her on political matters. This is evident from her correspondence to the grand viziers. Turhan's regency was marred by at least two factors: the war with the Venetians for the island of Crete, and the financial crisis that arose from the high expenses of waging war. Weak grand viziers did not improve the situation. However, in 1656 Köprülü Mehmed Pasha was appointed to the position of grand vizier. His condition upon accepting the post was that he be given greater authority than his predecessors. Thus, Turhan transferred her political power to that of the grand vizier. In 1657, During the long-term residence of Mehmed in Edirne due to the expeditions, Turhan Sultan was with him. During the short-term departure of Edirne, one of the viziers was appointed to supervise the sultan. She traveled to Istanbul from time to time while her