In the fourth book “Urartu,” the ancient kingdom of Van is at the center of the story. The fourth book “Urartu,” as the title suggests, takes us to the Caucasus. Not that we haven’t been here before—we remember the Scythian Khatrass and the Assyrian Ashshurrisau with their accomplices—but this time we’ll have to stay in these lands for a long time. For those who, in some incredible way, haven’t heard of Urartu, here’s a careful hint: it was a state in the Caucasus that existed roughly from the 8th to the 6th century BCE, and of course left an indelible mark on ancient history. This book also brings us fateful events in Nineveh and a journey to the Scythian king Ishpaqa’s camp—by the way, about the formidable neighbors of the Kingdom of Van…