Josephus, before becoming the great Jewish historian of the first century, led Jewish rebels against the Romans in defense of Jerusalem. But after the battle was lost, he surrendered to the Romans and won the favor of Rome, living out the rest of his life there as a successful writer. His story has led many to see him as a traitor to his people and his work as thinly disguised Roman propaganda. William den Hollander argues that this reading is mistaken (free registration required):
One of the key contributors to the negative assessment of Josephus’ character, which has also affected the manner in which his narratives have been read, has been the scholarly and popular misunderstanding of his relationship with the Roman generals/emperors. The traditional view has been that Josephus served as an imperial lackey and that his writings, in particular the Jewish War, were nothing more than works of propaganda advancing the interests of the imperial throne. Since the early 1980s, however, this view has been increasingly questioned by experts. By close examination of his narratives and careful contextualization of Josephus and his writings within ancient society, scholars have begun to recognize that his relationship with the emperors was not quite as close as had been assumed (or, perhaps, as close as Josephus wished to have us believe) and that, furthermore, his narratives do not quite fit the characteristic of propaganda. In fact, they are at times quite the opposite.
Read more on ASOR: http://asorblog.org/josephus-reconsidered/