Nehemiah ben Hushiel was a central figure in the Jewish revolt against Heraclius, (614-617 to 625 CE).

He is best known as a savior figure who appears in many medieval Jewish apocalyptic writings as the Messiah ben Joseph.

Nehemiah's background is speculative.

Loewenberg suggests that The Sassanian Emperor Khosrow II, anxious to court Jewish support in advance of his invasion of the Byzantine Levant, appointed Hushiel as Exilarch, with Nehemiah placed as the spiritual leader of the Jewish forces.

The Sassanians, commanded by Shahrbaraz, were joined by Nehemiah and the wealthy Jewish leader Benjamin of Tiberias, who had mustered a force of Tiberian Jews.

The combined force captured Jerusalem in 614 CE without resistance.

Jerusalemite churches were either destroyed or desecrated, and Nehemiah was installed as the new Jewish ruler of Jerusalem.

He began making arrangements for the Third Temple's construction, and sorting out genealogies to establish a new High Priesthood.

Nehemiah would have been keenly aware that his rulership had messianic overtones. Talmudic Rabbis were intensely focused on calculating the date of the Messianic age and the rebuilding of the third Temple, which was judged to begin in the late 6th C and climax in the early 7th C.

However, Sebeos wrote that Jerusalem's new Jewish and Arab leadership disputed over who could build a house of prayer on the Temple Mount.

The Arab authorities forced Nehemiah to build off to the side of the Mount, while the Arabs built their own prayer hall in the center.

After only a few months, a Christian revolt occurred. Nehemiah ben Hushiel and his "council of the righteous" may have been killed at this point, along with many other Jews, some throwing themselves off the city walls.

The surviving Jews fled to Shahrbaraz’s encampment at Caesarea.

The Jerusalem Christians held the city for 19 days before the walls were breached by Shahrbaraz’s forces.

In 617 CE, the Persians reversed their policy and sided with the Christians, probably because of pressure from Mesopotamian Christians. It has also been suggested that Nehemiah ben Hushiel was killed then.

At this point, Nehemiah's Temple Mount prayer hall was likely demolished.

The Arab prayer hall seems to have remained, even after Heraclius' subsequent retaking of the city.

The Frankish bishop Arculf visited Jerusalem in 679–688 and describes a rather ramshackle building:

“Near the wall in the east, in that famous place where once there stood the magnificent Temple, the Saracens have now built an oblong house of prayer, which they pieced together with upright planks and large beams over some ruins."

Very soon after, the Umayyad Caliph Abd al-Malik would begin construction of the Dome of the Rock.

For more reading, please check out the following articles:

Frank Meir Loewenberg (January 2012). "A Forgotten Chapter Of Jewish History: The Persian Conquest Of Jerusalem"
http://www.jewishmag.com/161mag/persian_conquest_jerusalem/persian_conquest_jerusalem.htm

Jacob Neusner (1970). "A history of the Jews in Babylonia v. later Sasanian times" https://books.google.com/books?id=zrM3AAAAIAAJ&pg=PA125&lpg=PA125&dq=Mar+Ahunai&source=bl&ots=WuG-5X9vnH&sig=kKtsqUjVHFfrBGHg60vrvW-fnQI&hl=en&sa=X&ei=NRTXUpWJHMjIkAePoYGYBA&ved=0CCcQ6AEwADgK#v=onepage&q=Mar%20Ahunai&f=false

Ian David Morris. "The Temple Mount Mosque in an Early Georgian Source"

http://www.iandavidmorris.com/the-temple-mount-mosque-in-an-early-georgian-source/

Manuscript illustration examples from a 14th c miniature of the Alexander Romance (apologies for the anachronism, but the manuscripts are too nice not to conscript into use here):

http://www.istitutoellenico.org/english/pubblicazioni/index5.html