The only ancient source of information about Masada is the writings of Josephus (Jewish Wars; Antiquities). According to him, the rock was first fortified by the Hasmonaean high priest Jonathan, who named it Masada ("the fort"). Jonathan may be identified with King Alexander Jannaeus of Judea (reigned 103-76 B.C.). However, it was actually King Herod (reigned 37-4 B.C.) who built the citadel, as a refuge against possible attack by the Egyptians or by descendants of the old Hasmonaean dynasty. Masada was held by a Roman garrison from 4 B.C. to 66 A.D., when the Jewish revolt began and the Zealots seized the fortress.
In 72, two years after the fall of Jerusalem to the Romans, the 10th Legion, led by the Roman governor Silva, encircled the stronghold with eight siege camps and built a ramp 300 feet (90 meters) high against the western side of the rock. The next year Silva breached the walls. The Zealots' leader, Eleazar Ben Yair, then persuaded the 960 men, women, and children in Masada to die free, and they killed each other.
In 1955-1956 a joint expedition of the Israeli department of antiquities, the Israel Exploration Society, and the Hebrew University of Jerusalem surveyed Masada and made trial excavations. A second joint expedition under Yigael Yadin excavated and restored 97% of the site in 1963-1965.
The oldest objects found on the top of Masada were coins from the reign of Alexander Jannaeus. All the large structures, dispersed over the plateau of 20 acres (8 hectares), which was surrounded by a casemate wall, had been built by Herod. The largest building was the western palace, Herod's principal residence. On the northern side of the rock, administrative buildings, storehouses, and a bathhouse had been erected, and a 3-tiered palace had been skillfully built on the edge of the cliff.
The buildings were plastered white, and some were decorated with frescoes. In the western palace were found two multicolored mosaics, the earliest of their kind yet discovered in the Holy Land. Great cisterns cut out of the side of the rock received water through an aqueduct.
The Zealots adapted the rooms in the casemate wall and in parts of Herod's palaces to their living needs. They built a synagogue, two ritual baths, and a religious schoolroom, which are the oldest known. The expedition found 700 ostraca (inscribed fragments of pottery), one of which bore the name "Ben Yair." Fragments of 14 scrolls of the books of Genesis, Leviticus, Deuteronomy, Psalms, Ezekiel, Ecclesiasticus, and Jubilee and a scroll belonging to the Dead Sea Scrolls' Community were also discovered. They were important for dating the Dead Sea Scrolls.
Remains of domestic utensils were in the ashes of the Zealots' dwellings. Parts of weapons, including rolling stones and stone balls used against the Romans, bear witness to the drama of Masada. Roman coins left by the Roman garrison between 73 and 111 A.D. and a church and some rooms built during the Byzantine period (5th-6th century A.D. ) complete Masada's story.