What is Horwitz’ principle argument in his book, A Voyage Long and Strange?

In “A Voyage Long and Strange,” Horwitz is surprised to learn how little he knows about the Europeans who “discovered” America. (One thing he does remember from college is to wrap those scare-quote marks around politically contentious words like “discover.”) His astonishing ignorance dawned on him during a visit to Plymouth Rock. “I’d mislaid an entire century, the one separating Columbus’s sail in 1492 from Jamestown’s founding in 16-0-something,” he writes. “Expensively educated at a private school and university a history major, no less! I’d matriculated to middle age with a third grader’s grasp of early America.”

Horwitz resolves to remedy his ignorance by embarking on an intensive self-tutorial mixed with lots of reporting and running around. He looks for Columbus’s remains in the Dominican Republic; tracks Coronado through Mexico, Texas and even Kansas; sifts evidence of the Vikings’ landing in Newfoundland; and gives the Anglos their due in tidewater Virginia. The result is popular history of the most accessible sort. The pace never flags, even for easily distracted readers, because Horwitz knows how to quick-cut between historical narrative and a breezy account of his own travels. It’s the same method he used in “Confederates,” deployed with the same success, and unlike many other, less journalistic histories, in which the material is displayed at a curator’s remove, it has the immense value of injecting the past into the present showing us history as an element of contemporary life, something that still surrounds us and presses in on us, whether we know it or not. Usually not.

Explanation:

on the morning of  july 21,  1861, general mcdowell ordered the  unionarmy to attack. it was on this hill that  confederate  colonel thomas jackson and his forces held back theunion  troops.