Large, open battles in the field were somewhat infrequent during this time. The armies were often occupied with counter-guerilla actions which led to a siege of the stronghold of the enemy. During sieges, the Roman Legions came to rely on missile power. This can be seen during the Jewish Revolt. In the siege of Jotapata in AD 68, Vespaianus or Vespasian was said to have at least 350 artillery pieces along with 7,000 auxiliary archers. He used these to bombard the enemy fortifications to start each day's attack. When Titus, Vespaianus' son, laid siege to the city of Jerusalem two years later, he reportedly had 700 pieces of artillery.