Royals Charles Spencer on His Newest Book: 'It's 'Game of Thrones' Meets 'Titanic' ' "Once people get over going back 900 years, it's a very recognizable story with fallible human beings," Charles Spencer tells PEOPLE Royals By Michelle Tauber Michelle Tauber Twitter Michelle Tauber is the Senior Editor overseeing Royals coverage at PEOPLE People Editorial Guidelines Published on September 16, 2021 04:15 PM Share Tweet Pin Email Charles, 9th Earl Spencer. Photo: David Buchan/Getty Images Charles Spencer tackles a screen-worthy chapter in royal history with his new book. In The White Ship, historian and 9th Earl Spencer explores a disaster that changed the course of the monarchy forever: the maritime disaster in 1120 that killed 300, including King Henry I's heir, William Aetheling. "It is Game of Thrones meets Titanic," Spencer tells PEOPLE Royals in the new fall issue, on newsstands now. "And once people get over going back 900 years, it's a very recognizable story with very fallible human beings." In the book, which is already a bestseller in the U.K. and is set for release in the U.S. on October 19, Spencer examines the shocking brutality of Henry I, whose success at maintaining safety for his subjects at home came with the cost of his fearsome tactics with foes. "If you wanted to be a successful ruler in Europe in the 12th century, you had to make people scared of you," says Spencer. Meanwhile, his heir William Aetheling was a fun-loving 17-year-old when his reckless partying led to the devastating shipwreck. "It's the medieval version of drunk driving," says Spencer, "where the teenagers get riotously drunk and then encourage the crew, to whom they're entrusting their lives, to join in the drinking. And guess what? They hit a rock, the ship goes down and all but one person on board drowns. For more royal insights, including glamorous photos and inside stories, pick up a copy of PEOPLE Royals, on newsstands now! "It's an incredible lesson," he continues. "The king, who insisted on going on his own ship with the grown-ups and then left his teenage son on board the most exciting ship, the White Ship, was tempting fate. It's certainly not his fault, but you can see how it happened."