When he assumed his nation’s highest office, he had no previous governmental experience. Born wealthy, he’d never worked for anyone else. Now his nation’s commander in chief, he had never served in the military.

For his every move, he relied on a secretive, eccentric advisor bent on reshaping the nation’s political order. Demanding absolute loyalty, the new ruler did not trust anyone more popular than he was, and detested all opposition.

If these facts sound familiar, they fit not only President Donald Trump but America’s last king, George III.

He came to power at the moment of England’s greatest glory, its defeat of France for control of North America.

For a century after a bloody civil war that had ended with the beheading of its king, England’s monarchs had reigned, not ruled, all power vested in Parliament. Ministers backed by Parliament ruled.

Since the Restoration, monarchs had contented themselves with acquiring estates and amassing art collections — and lovers. They concentrated on maintaining a Protestant dynasty and defeating the hated French in a contest for global monopoly. Only one ever tried to turn back the clock to a powerful monarchy. He was forced to throw his mace into the Thames and flee for his life.

George III, shunned by his dissolute father, lived with his mother and eight siblings until the day he inherited the throne. Home-schooled by the reclusive John Stuart, Earl of Bute, he learned to abhor Parliament and opposition of any kind.

Still unmarried when a courier interrupted his daily ride to tell him the old king was dead, George promptly fired his brilliant and popular prime minister, William Pitt, replacing him with his tutor, a man so unpopular that crowds often attacked his carriage.

While George prided himself on being the first Hanoverian king born and bred in Britain, he feared an Englishwoman would have powerful court connections. Bute advised him to seek a bride in Germany, home of his ancestors. George never met 17-year-old Charlotte of Mecklenburg-Strelitz until she arrived with her ladies-in-waiting and went right into isolation. She soon began to bear George’s 14 children.

Suffering from porphyria, a rare hereditary metabolic disorder, George took advantage of severe insomnia — he once went entirely without sleep for 72 hours — to write nocturnal notes, letters, critiques of cabinet ministers and generals, letters to citizens with complaints. Nothing was too great or trivial, from the stipends of parish clergy and the royal laundress’s pension to his comments on military campaigns.

Obsessed with time and timepieces — he gave Charlotte 24 bejeweled clocks for their bedchamber — often before five in the morning he dipped his quill, noting the minute and the hour atop each missive. Even as Parliament refused to pay for a private secretary, George advocated importing cheaper workers to drive down wages and increase employers’ profits.

Living frugally day to day, he lavished money on renovating the new royal residence, Buckingham House. In private, he entertained his queen by playing the harpsichord; they sang and conversed in German. She loved opera; he, theatre. He first acted in a Roman play at 10. He roared his approval at David Garrick’s plays.

And George III chose a playwright as the commanding general of his most fateful military expedition.

At first, as Americans protested Parliamentary taxes, George wrote he believed the “mother country” should practice “moderation” and “firmness” with her recalcitrant colonies. But after the Boston Tea Party, he wrote, “The colonies must either submit or triumph. . . . We must not retreat.”

The first year of the American Revolution went badly for the British. Bloodied at Concord and Bunker Hill, stymied by Benedict Arnold’s navy on Lake Champlain, nearly losing Canada and repulsed at Charleston, the first British commanders felt the wrath of George’s disapproval.