500
When Vespasian became ruler, his main military mission was to conquer Judea, as you know. In this process he slaughtered thousands of Jews in his path and to many Roman citizens, this changed their image of him.
What is changing point of views. By killing all these Jews, Vespasian changed many peoples point of views. Many Roman citizens did not think that these murders were right and these people started to turn against him. This made him not successful for a short time but people shortly forgot about what happened when Vespasian reformed the tax system