If you were to take a survey of the top ten Jews in the Bible, Joshua might not even make the list. Higher up would be people including:
* Abraham, the first Jew
* Joseph son of Jacob, the original Horatio Alger story
* Moses, who brought the Jews out of Egypt
* Samson, toughest hippie ever.
* David, the second legitimate Jewish King who also slew Goliath
* Solomon, best king ever.
* Job, most positive screwed over guy in history
* Elijah, proof that cleanliness is not godliness.
* Esther, only woman in history to engineer a genocide (runner up Helen of Troy).
* Isaiah, visualized a Messianic Jewish movement that wound up legitimating Christianity
* Jesus, duh!
This isn't really fair. Joshua, after all, put Jews on the map. Literally.
Who was he?
Joshua was the Jewish warlord (the first "Judge") who, in a single lifetime, took a rag tag nation of about a couple million* half-starved lapsed semi-nomadic Jewish herders out of the wilderness, rededicated them to their ancestor's faith,** took them across the river Jordan into Canaan, conquered about 90% of modern day Israel, and divided up the spoils among his people's dozen or so tribes.
Before Joshua, the Jews were a people without a country. After Joshua, they were the dominant inhabitants of the Levant from the foothills of the mountains of Lebanon to the Sinai.
Joshua may or may not be an authentic historical figure. But, clearly, there was somebody like him even if the actual historical figure wasn't much like the guy described in the Biblical story. Somebody created huge swath of Jewish territory that hadn't been ruled by them for at least most of the Bronze Age and the time before then, probably mostly in a single pretty dramatic extended campaign of conquest (a familiar pattern in history).
Honestly, there are far more reason to doubt the historical authenticity of Moses than Joshua. Abraham and Moses could easily have been invented or radically reinvented to justify the horrifying actions of Joshua in retrospect. Abraham and Moses didn't have to exist to have mythical power in Joshua's present, any more than Noah or Adam did. But, Joshua, or someone like him, really did have to exist in the real world.
As an anthropologist and historian, one wants to ask what it was the allowed them to prevail, again and again, over the existing "Palestinian" residents of Canaan. Arguably, the Book of Joshua is Exhibit 1 in the case that a religion can confer selective advantage on communities that adhere to it.
The Jews would remain the dominant inhabitants of that region until the Kingdom of Israel in the North fell to the Assyrians about two and a half centuries the Jewish kingdom was divided, and then the Kingdom of Judah in the South fell to the Babylonians after almost four centuries as a divided Kingdom. Three successive legitimate kings of a united monarchy preceded these kingdoms. Between Joshua and Saul, the first legitimate Jewish King, were a succession of temporary warlords and one illegitimate king, coming to the fore to lead the very loosely confederated Jewish tribes.
After about 50,000 exiled Jews returned from exile, according to the Biblical account, Jewish self-governance was restored for another five centuries, although mostly as a dependency of one foreign state and then another, until the diaspora ca. 70 CE.
One also wants to ask what happened in that diaspora process in a supposedly well documented historical period to one of the most literate people that the world has ever known. Surely many, maybe many millions were exiled. But, surely too, not all of them were. Where are the genetic and cultural traces of this people who seemingly dissolved into thin air in the Levant? To what extent are the modern Palestinians ancestors of the Biblical Jews, and to the extent that they are not, how did they get there?
Nineteen centuries later, the Jews of the diaspora started to return to the land that Joshua had conquered united by their myths about this land that most of them had never seen and didn't know anyone who had, and in 1948 with British patronage and as a sort of consolation prize for a people who had just endured the Holocaust at Nazi hands, Israel was restored again as a Jewish nation that has managed to stay in existence for 66 years, to the great annoyance of the Palestinians they displaced and more or less all of the other countries in the vicinity.
There is irony in that. The Holocaust was the last in a long line of genocidal against the Jews that the Jews who remain today survived. Yet, the formative act of the Jewish people by which they came to be the dominant peoples of Canaan were a series of genocides directed at the modest sized Canaanite tribes who stood in their way and controlled the land of milk and honey that they said that their God promised them.
In part as a result, the Jews have not been really all that successful at the whole being fruitful and multiplying thing. Abraham's children are not as numerous as the stars or the grains of sand on the beach. There are only seven or eight times as many Jews in the world today as there were three thousand years or so ago at the time of the census in the Book of Numbers (although that figure may have been exaggerated). The world as a whole has about 10,000 times as many people as it did then.
The Palestinians and their supporters don't have much good to say about the decision of the Jewish people to restore Joshua's nineteen century lapsed accomplishment. But, no one can reasonably dispute that the means by which the Jews took control of Israel in the first half century of the 20th century and the way they treated the land's previous inhabitants, was positively saintly and humane by comparison to the means which the Book of Joshua (the first book of the Hebrew Bible after the Torah concludes) asserts that they made their first conquest. The account in the Book of Joshua is stunning, as much as anything else, because even though the story was set down many centuries later, it is recounted with no sense of shame or guilt.
The Book of Joshua is an almost unique anthropological document. Ancient history and prehistory is awash with the rise and fall of peoples and empires. But very few recount in detail the process and ideology of the nitty gritty process of the conquests.
* Numbers reports about 630,000 adult male Jews. Assuming an equal number of women, and about two-thirds as many children and non-Jewish servants as there were adults, the census population of the Jewish people would be about two million. Realistically, this is almost surely impossible. The arid region between Egypt and the Jordan River simply cannot support that many herders with early iron age technology. Quite plausibly, this may have actually been the population of Israel around the 8th to 5th centuries BCE when Numbers was written, without adjusting for population growth in the previous centuries. At a 3% per annum growth rate, typical of high population growth periods for undeveloped countries, one gets a more plausible census population closer to a more reasonable number of about 30,000 at the time of Joshua, with a substantial margin of error due to uncertainty in the length of that time period and the actual population growth rate.
** In the Biblical account there were no circumcised young men left in exile; the young men who were soldiers at the time of exile forty years earlier had all died in losing battles since then and their surviving wives, daughters and son had not kept the faith.