Upstate New York in the early 19th century was known as the “Burned-Over District,” on account of the wildfires of religious enthusiasm that regularly swept through the area. The revivals came and went, but one of the preachers to emerge from the Burned-Over District turned out to be the founder of an enduring new faith—Joseph Smith, the creator of Mormonism. So, too, with Judea in the 1st century C.E. The Jewish population, filled with resentment for their Roman occupiers and for the priestly class that collaborated with the Empire, had an insatiable appetite for prophets and preachers. Our best source for Jewish life in this time and place, Josephus’ The Jewish War, is like a roll-call of self-declared messiahs. One of these, known only as “the Egyptian,” led 30,000 Jews in a march on Jerusalem, threatening to seize power; another, a rabbi named Judas, tried to convince the Jews to stop paying taxes and to accept God alone as their ruler. But of all those charismatic figures, only one is remembered today: Jesus of Nazareth.Although Reza Aslan’s new biography of Jesus is titled Zealot, he acknowledges that Jesus was not, strictly speaking, a Zealot at all. The capital-Z Zealots were a revolutionary political party that emerged in Jerusalem at the time of the uprising against Rome in 66 C.E., long after Jesus died. But the idea of “zeal,” in Hebrew kinah, had a long and potent history in Judaism, dating all the way back to the Israelites’ wandering in the desert. The original zealot was Phineas, the grandson of Aaron, who in the book of Numbers impales an Israelite and his pagan bedmate with a javelin. This murder wins God’s strong approval: “Phineas … has turned my wrath away from the children of Israel, because he was zealous for my sake.” Zeal, then, is a jealous passion for the sanctity of God and a fierce desire for revenge on God’s enemies.In Judea at the time of Jesus, zeal was both a religious passion and a political one. God had promised the land of Israel as an inheritance for his people forever; yet now the Romans were in charge, their troops guarding the Jerusalem Temple, their tax-collectors feeding on the livelihood of the poor. In these circumstances, the desire for national independence was at the same time a longing to restore God’s sovereignty. The two motives combined in the idea of the Messiah, a figure who was supposed to be both a divine redeemer and an earthly king. It was this fusion of worldly and otherworldly grievances that made Judea such a difficult place for the Romans to govern: Every time a legionary misbehaved, the Jews were offended on God’s behalf. There were so many of these provocations that, reading Josephus, one has the impression that the disastrous rebellion of 66 was only a matter of time.For thousands of years, however, Christianity tended to remove Jesus from this historical context. Starting with Saint Paul, Christian doctrine emphasizes Christ as a cosmic principle—the Logos, the son of God—at the expense of Jesus as a human being. It was only with the rise of the “quest for the historical Jesus,” in the biblical criticism of the 18th century, that Christians began to acknowledge that Jesus was a Jewish preacher, whose ideas about God and redemption were drawn from the common culture of his time.To understand Jesus, Aslan argues in Zealot, it’s necessary to understand that culture and the zeal that was at its core. Drawing on a well-established body of scholarship, Aslan paints a vivid, accessible portrait of Jesus as a Jewish nationalist, “a zealous revolutionary swept up, as all Jews of the era were, in the religious and political turmoil of first-century Palestine.” He knows that, even now, this idea will come to many Christian readers as a shock: The real Jesus, he writes, “bears little resemblance to the image of the gentle shepherd cultivated by the early Christian community.”There are, of course, some serious problems facing anyone who wants to write about the historical Jesus. Like Moses, Buddha, or Muhammad, Jesus is known to us not through objective documents—the earliest secular reference to him comes in another work by Josephus, written some 60 years after his death—but through religious scriptures. And these scriptures—the Gospels, Acts, the letters of Paul—are, as Aslan shows, the products an internal Christian struggle to define just how Jesus should be remembered. Their goal was not factual accuracy but spiritual truth, which makes it very hard to evaluate them as historical evidence.In Jesus’s case, the Gospel writers were driven in large part by the need to make his story conform with pre-existing Jewish expectations about the Messiah. Understanding this helps us make sense of some of the conflicts and contradictions in the four Gospels. Aslan takes as an example the problem of figuring out just where Jesus came from. Everyone familiar with Christmas carols knows that Jesus was born in Bethlehem; yet he is also known as Jesus of Nazareth, a small town in the Galilee.To explain this discrepancy, the gospel of Luke invents a deeply implausible story about how, just before Jesus’s birth, his parents traveled from Nazareth to Bethlehem, to comply with a Roman census. The details make no sense, but as Aslan explains, that was beside the point. Jesus had to be given roots in Bethlehem so that he could be born in the same city as King David—the Messiah, after all, was supposed to be a descendant of David’s house.The paradox of writing about Jesus is that we can only form an idea of him from the scriptures we have, yet we can only evaluate the scriptures if we have an idea of what he must have been like. Aslan marches boldly into this vicious circle, guided by the certainty that the real Jesus must have been, above all, a Jewish zealot. He was a figure like “the Egyptian,” or the rabbi Judas, or for that matter John the Baptist: a religious virtuoso who played on the familiar tropes of Jewish grievance to ignite a mass movement. “The new world order he envisioned,” Aslan writes at characteristically high volume, “was so radical, so dangerous, so revolutionary, that Rome’s only conceivable response would be to arrest and execute [his followers] for sedition.”There is much to be said for this point of view, and Aslan’s reading of the Gospels helps to clarify some of their ambiguities. Take, for instance, the moment when Jesus is asked, “Is it lawful to pay the tribute to Caesar or not?” In response, he takes a coin and asks whose picture is on it. “It is Caesar’s,” comes the reply; to which Jesus says, “Render therefore unto Caesar the things that are Caesar’s, and unto God the things that are God’s.” At least, that is how the King James Bible translates his words; and in this form, their message seems to be a kind of political quietism. Keep paying taxes, Jesus seems to advise, and obey the government, since money and worldly affairs are the government’s concern. But entrust your soul, which is what really counts, to God.Aslan, however, shows that the same passage can be translated quite differently: “Well, then, give back to Caesar the property that belongs to Caesar, and give back to God the property that belongs to God.” Read this way, Jesus sounds much more like a zealot, demanding that the land and people of Israel—which are God’s property—be returned to God and freed from Roman control. It is sayings like this, Aslan writes, that led Jesus to be labeled a “bandit”—a term that was used for all sorts of popular revolutionaries in Judea. When Jesus was crucified next to two “bandits,” then, we should not understand this to mean thieves, as though the Romans were devising an insult to Jesus. Rather, he was crucified next to fellow rebels, whose crime, like his, was agitating for Jewish independence.All of this adds up to a coherent and often convincing portrait of who Jesus was and what he wanted. The problem, which Aslan acknowledges though he doesn’t fully address it, is that the Jesus of the Gospels is much more than a Jewish nationalist. If he were simply a zealot, he would not be remembered today, any more than “the Egyptian” is. When Jesus spoke about God as his Father, or called himself the Son of Man, or said that the Kingdom of Heaven was coming, his words did have a political bearing, as Aslan shows; but they also had a much broader and more mysterious application. Jesus, one might say, radicalized the language of Jewish messianism in such a way that it could be turned against Judaism itself. This act of religious creativity, more than his zeal, is what turned a minor Jewish preacher and miracle-worker into the Christian son of God.***Like this article? Sign up for our Daily Digest to get Tablet Magazine’s new content in your inbox each morning.Adam Kirsch is a poet and literary critic, whose books include The People and the Books: 18 Classics of Jewish Literature.