During 16th and 17th century, chief consort of the sultan received title "haseki sultan" or sultana consort. This title surpassed other titles and ranks by which the prominent consorts of the sultans had been known (hatun and kadın). When the position of valide sultan was vacant, a haseki could take valide's role, have access to considerable economic resources, become chief of imperial harem, sultan's advisor in politic matters, and even have an influence upon foreign policy and on international politics. These cases happened during Hürrem Sultan and Kösem Sultan's periods.