Thanks For Your Last Answer. I Have Seen Many Times That You Are Calling "hurrem" As Queen, U Also Said

Thanks for your last answer. I have seen many times that you are calling "hurrem" as queen, u also said that hurrem is the only queen the ottoman had. Can please refer some qoutation for it except pierce"s book? thanks in advance.

That's because Hürrem is the only Ottoman consort similar to a European queen consort.

Sultan Süleyman promoted one of his concubine wives (Hürrem) to the position of married wife (sultan = queen) by freeing her. It is an unprecedented situation in the history of the dynasty that Hürrem received a "certificate of freedom" from Süleyman, married him, and became a "haseki sultan" (queen). — Sakaoğlu, Bu Mülkün Kadın Sultanları

This is how Sakaoğlu presents Hürrem before talking about her:

The only queen of the Ottoman dynasty, married wife of Suleiman the Magnificent, mother of Selim II (1566-1574). Since she died before her son Selim's sultanate, she is not mentioned as "mehd-i ulya-ı saltanat" (Valide Sultan). On the other hand, she was "Hürrem Haseki" during her husband's reign; she became famous with the titles of "Haseki Sultan" and "Hürrem-Shah" after obtaining the sultanate (queenhood).

Sakaoğlu uses the term kraliçe when talking about her (and only about her), which means queen, and is never used for Ottoman consorts (in Turkish)... except for Hürrem.

She's different from the other haseki sultans:

In the 16th-18th centuries, the honorary title "haseki" was given to the concubines of the sultans who gave birth to princes and who were at the top of the sultan's wives.

While I don't necessarily agree with the giving birth to princes thing, I understand what he means when he says that: the following haseki sultans were not like Hürrem and would never be. The most similar to her could be Nurbanu — because Selim II married her with the clear goal of repeating what his father had done — but she too is not like Hürrem: during Süleyman and Hürrem's times you actually see a monogamous marriage. They're like a European royal couple and this would never be repeated (Selim II had other children after Nurbanu's, Murad III stopped being monogamous after some time, Ahmed I too had a lot of minor  — and unknown —  consorts and children).

This is why Hürrem is the only queen that the Ottomans ever had.