Masada became famous for its significance in the First Jewish-Roman War (Great Jewish Revolt), when a siege of the fortress by troops of the Roman Empire led to a mass suicide of the site's Jewish defenders when defeat became imminent.
The cliffs on the east edge of Masada are about 451 m high, dropping off to the Dead Sea, and the cliffs on the west are about 100 m high; the natural approaches to the cliff top are very difficult. The top of the plateau is flat and rhomboid-shaped, about 600 by 300 m. The center of the plateau is at 31°18′55″N, 35°21′13″E. There was a casemate wall around the top of the plateau totaling 1400 m long and 4 m thick with many towers, and the fortress included storehouses, barracks, an armory, the palace, and cisterns that were refilled by rainwater. Three narrow, winding paths led from below to fortified gates.
According to Flavius Josephus, a First century Jewish Roman historian, Herod the Great fortified Masada between 37 and 31 BCE as a refuge for himself in the event of a revolt. In 66 CE, at the beginning of the First Jewish-Roman War (also called the Great Jewish Revolt) against the Roman Empire, a group of Jewish rebels called the Zealots (kana'im, "zealous ones") who objected to Roman rule of Judea (as the Roman province of Iudaea, its Latin name). Commanded by Elazar ben Ya'ir (who may have been the same person as Eleazar ben Simon), the Zealots took Masada in 68 from the Roman garrison (see also Roman Legion) stationed there. After they persuaded the Romans to disarm they then slaughtered every man of it. In 70, they were joined by additional Zealots and their families who were expelled from Jerusalem by the other Jews living there shortly before the destruction of Jerusalem (and the Second Temple), and for the next two years used Masada as their base for raiding and harassing Roman and Jewish settlements alike.