Will the Dajjal emerge before or after the Righteous Islamic Caliphate?

If the intended meaning of "the Rightly Guided Caliphate" is the Caliphate of the Mahdi, then it appears from the hadiths that his emergence will be before the Dajjal. It is authentically reported in Sahih Muslim that when the conquests reach Constantinople, Satan will cry out, "The Dajjal has taken your place among your families."