The present building of this mausoleum, which is visited by Jewish pilgrims from all over the world, has nothing to speak about from the architectural point of view. Under its simple brick dome there are two graves with some Hebrew inscription up on the plaster work of the wall. Two exquisite wooden tomb-boxes are also to be seen, one of which is of an earlier date and bears an inscription in Hebrew.
The original structure dates to the 7th Century A. H. [13th Century A.D.] and it might have been erected over other and more ancient tombs. The exterior form of this mausoleum, built of brick and stone, resembles Islamic constructions, and the monument consists of an entrance, a vestibule, a sanctuary and a Shah-ni-shin (King’s sitting place). Some believe that the mausoleum is the resting-place of Esther, the Persian Queen and wife of Xerxes (Khashayarshah) and the second tomb belongs to her uncle, Mordecai [Mardocai].
Source: www.biblediscovered.com