Of all the British monarchs who have claimed that they have ruled the seas, only one, King William IV, has been a truly professional seafarer. Known as the "Sailor King" in his own lifetime, he saw himself as a naval officer who happened to become the sovereign rather than a monarch who had been a naval officer. His life presents an appealing, if sometimes shocking character. His life in the Royal Navy was fraught with crisis: rivalries, doomed love affairs, extravagance and rebelliousness. Often he seems a Hogarthian character, or a nautical version of the Regency rake. Yet, while many mocked or despised him, there were those who loved him. And, when he came to the throne and was all but swept away by the tide of the Age of Reform, he faced it with resolution and survived with honour. He had overcome the pressures and contradictions of a royal upbringing, to end his days a king who was not only loved but admired for setting an unstable monarchy on an even keel for the long reign of his niece Victoria which followed his.

The real life story of the Plantagenet ruler, by “the most remarkable medieval historian of our time” (The Times, London). The talented, confident, and intelligent son of John of Gaunt, Henry IV started his reign as a popular and charismatic king after he dethroned the tyrannical and wildly unpopular Richard II. But six years into his reign, Henry had survived eight assassination and overthrow attempts. Having broken God’s law of primogeniture by overthrowing the man many people saw as the chosen king, Henry IV left himself vulnerable to challenges from powerful enemies about the validity of his reign. Even so, Henry managed to establish the new Lancastrian dynasty and a new rule of law—in highly turbulent times. In this book, noted historian Ian Mortimer, bestselling author of The Time Traveler’s Guide to Medieval England and The Time Traveler’s Guide to Elizabethan England, goes beyond the legend portrayed in Shakespeare’s history play, and explores the political and social forces that transformed Henry IV from his nation’s savior to its scourge.