“Josephus describes the A.D. 66-70 war in great detail, especially in his The Wars of the Jews. Two events are important for our study. At the outset of the war, A.D. 66/67, the legate of Syria, Cestius Gallus, approached Jerusalem with the Twelfth Legion and occupied the northern suburb, Bezetha. Realizing he did not have sufficient forces to take the rest of the city he withdrew. His army was ambushed in the Beth Horon pass and suffered heavy losses. This victory added prestige to the Jewish rebels and increased hopes of eventual victory over the Romans. In the late spring of 68 the Roman general Vespasian had reduced the region beyond the Jordan, western Judaea, and Idumea to the south. At this point the death of Nero and civil war in Rome caused Vespasian to temporarily halt military operations in Judaea to await the outcome of developments in Rome — he was eventually elected Emperor. This provided the Jews with an unexpected respite which many interpreted as divine intervention on their behalf.
When finally the Romans attacked Jerusalem they did so with four Legions. The Fifth came from the west and camped on the west side of the city. The Fifteenth and Twelfth Legions came generally from the north and eventually encamped on Mt Scopus. The Tenth Legion, after subduing Jericho, attacked from the east and camped on the Mount of Olives…”
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http://www.preteristarchive.com/Bibliography/1998_scott_flee-pella.html