Letter For The King Is Based On A Book That Desperately Needed More Female Characters

Netflix's YA fantasy series The Letter for the King has plenty in common with Game of Thrones — including the fact that it's based on a book of the same name. But unlike GoT and its still-unfinished George R.R. Martin novels, this one's entirely finished — and it has been for almost 60 years.

Dutch writer Tonke Dragt published her children's book De Brief voor de Koning in 1962, winning the Dutch children's book of the year award in 1963, and even winning a major award in 2004 for the best Dutch children's book of the past 50 years. Per the book's publisher, Leopold, the book has sold more than 1 million copies worldwide and has been translated into more than a dozen languages — including English, though that edition didn't hit bookshelves until 2013.

A review in The Guardian after the book's English publication pointed out just two small supernatural elements in the story — meaning that one of the biggest differences between the book and the series is the addition of magic. There's no prophecy and no, um, whatever that glowing thing was at the end of the series.

The other major difference: The character of Lavinia is just a girl our hero Tiuri meets on his journey, not the person who would become his partner in the quest. Tiuri did have a buddy on his quest in the book, but it was actually a mountain guide named Piak. Also Queen Alianor didn't exist at all — the strong female characters were added just for the Netflix production.

One similarity: "At the end of the book, a jester tells Tiuri a story about a man who chased a rainbow: 'he realised that what mattered was not the rainbow itself but the search,'" the review points out. That's an applicable parable for the ending of the series, too (if you know, you know).

The series isn't the only adaptation of the novel. Before Netflix got a hold of the story, a Dutch film written by Maarten Lebens and Pieter Verhoeff hit theaters in 2008.

Though the book didn't get its English-language release until 2013, it's been a classic in Europe for decades. In fact, three Scandanavian stars of the show — Gijs Blom, who plays the evil Prince Viridian; Jakob Oftebro, who plays the gallant Prince Iridian; and Yorick Van Wageningen, who plays the regal King Favian — all read the book as children.

Star Amir Wilson, who plays knight-in-training Tiuri, told Entertainment Tonight that the series expands the world of the book in its introduction of many more characters.

"We have more than one storyline to follow. We have so many different people and you get to follow each one and follow their journey," he said.

Added star Thaddea Graham, who plays independent young novice Iona, "We take a modern take on a classic story and the messages are still very much the same. We just try to let it resonate with a modern audience and I really think it pays off."

The biggest change was also the most important for Ruby Ashbourne Serkis, who plays Lavinia: "the writers did a really good job of bringing strong female characters into it, which is really important especially for today," she told ET. "Some of the strongest characters in the show are female and they weren't in the book."