Michael Bond, author of the beloved Paddington Bear books, passed away at 91 on Wednesday. The author of children’s series that included characters such as Olga da Polga and Monsieur Pamplemousse, he was most widely known for over two dozen books about the foundling Paddington, which have sold over 30 million copies around the world since 1958.

As many children and parents from throughout the last half century know, the Paddington Bear story goes as follows: The Brown family finds a bear from “darkest Peru” sitting on a suitcase at London’s Paddington train station. He has a note hanging around his neck that says “Please look after this bear.” The family takes him in and he embarks on a series of entertaining adventures.

In a 2014 interview with The Telegraph, Bond said the character was partially inspired by Jewish refugee children he had seen arriving at London’s Reading train station during World War II.

“I remember their labels round their necks and then I remember going to the cinema and seeing on the newsreel that Hitler had moved into some new country and seeing footage of elderly people pushing prams with all their belongings in them. Refugees are the saddest sight, I still think that,” he said.

From 1938-1940, rescuers brought about 9,000-10,000 children to Great Britain from Germany, Austria, Czechoslovakia and Poland in what became known as the Kindertransport. Some 7,500 of these children were Jewish, according to the United States Holocaust Memorial Museum.

Bond, who attended a Catholic school as a youngster, also told The Telegraph that he was upset about a non-Jewish casting choice made for the 2014 Paddington movie. Jim Broadbent, known for his performances in films such as “Moulin Rouge!” and the Harry Potter franchise, was chosen for the role of Dr. Gruber — an antique shop owner who becomes one of the bear’s best friends.

“It’s not his fault, but it does bother me because I’ve such a clear picture of Dr. Gruber. I wanted someone foreign because he was based on my first agent, a lovely man, a German Jew, who was in line to be the youngest judge in Germany, when he was warned his name was on a list, so he got out and came to England with just a suitcase and £25 to his name,” Bond said.