“Why for 53 years I’ve put up with it now!”

So laments the Grinch, the titular character of Dr. Seuss’s holiday masterpiece How the Grinch Stole Christmas. The book was an instant classic when it was released in 1957, the same year its author turned…53.

It’s not a coincidence.

Yes, fans of the lovable, silly, jolly genius behind The Cat in the Hat and Green Eggs and Ham might be surprised to learn that the inspiration behind the Grinch was none other than Seuss himself, Theodor Geisel.

“I was brushing my teeth on the morning of 26th of last December when I noted a very Grinch-ish countenance in the mirror.” Geisel said in a 1957 interview with Redbook magazine. “It was Seuss!”

Fed up with the noise, the activity, and what he viewed as the commercialism and sheer busy-ness of the season, he longed for a return to the peace and serenity of holidays past.

“Something had gone wrong with Christmas, I realized, or more likely with me,” he said. “So I wrote a story about my sour friend, the Grinch, to see if I could rediscover something about Christmas that I’d obviously lost.”

The book took only weeks to finish. Writing from a place of personal discovery made How the Grinch Stole Christmas “the easiest book of my career to write” with one notable exception: the ending.

Although he knew he wanted the Grinch to realize the true meaning of Christmas, he struggled with how to do it. Not wanting to come across as too preachy or foray too deeply into religious themes, Geisel wrote and re-wrote the ending several times before settling on one.

“Finally, in desperation,” he said, “without making any statement whatever, I showed the Grinch and the Whos together at the table, and made a pun on the Grinch carving ‘roast beast.’ I had gone through thousands of religious choices and then after three months, it came out like that.”

Despite its stark departure from other Seuss books, being the first one to feature an adult AND a villain as the main character, the book was an instant success, spawning a well-known cartoon special as well as several sequels and movies. Fifty years after its original release, it was named in the National Education Association’s “Teachers’ Top 100 Books for Children” and, in 2012, was named in the list of “Top 100 Picture Books” by the School Library Journal.

As for Seuss himself, he continued writing, ultimately creating more than 60 books for children over the course of his career. But How the Grinch Stole Christmas, his most surprisingly autobiographical, remained near and dear to his heart his entire life. How do we know? Spotted on his license plate as he drove around his La Jolla, California neighborhood was one word:

GRINCH