British author Terry Deary is bringing an end to his much-loved "Horrible Histories" series for children after 20 years of the gruesome volumes, he said on Tuesday.
"It has naturally come to an end, the way things do," the 67-year-old told The Times newspaper. "It has had a good run, it's had a better run than most children's series."
From "The Rotten Romans" to "The Frightful First World War", Deary has penned more than 60 of the books, selling over 25 million copies in 40 countries.
Illustrated by Australian artist Martin Brown, the series revels in the "wicked, weird and woeful" details of history -- such as why rich Romans had to use a vomitorium, and how England's Tudors boiled some prisoners alive.
The series, which has been translated into 25 languages, has also spawned a BBC television show and a stage production over the years.
Deary said his publisher Scholastic had not officially told him that the series was ending, but there was "a general feeling there will be no more".
"Deadly Days in History" will be published in 2013 to mark "20 horrible years" of the books, but he expects it to be the last.
Following in the footsteps of Harry Potter author JK Rowling, he will now try his hand at writing for adults -- signing up for a four-part history series on the Roman Empire, the Elizabethans, the Vikings and the Victorians.
Deary did not excel at history at school. As a teenager he got a mediocre C grade in his O-level history examination, and narrowly avoided failing his history A-level a couple of years later.
"His history lessons were so boring and so badly taught that he learned to loathe the subject," his website says. "Horrible Histories is his revenge."
Deary said he would not miss writing the books as he was tired of his publisher pressing him to write on topics he knew nothing about, with only a few months to do the research.
"You have to immerse yourself in a new subject and hope there's something horrible to write about," he told The Times. "There usually is."