In 1971, Christian’s owners published his story as A Lion Called Christian. This book was republished in 2009 following the spread of his story on YouTube.
“Christian was a lion originally purchased by Australians John Rendall and Anthony “Ace” Bourke from Harrods department store of London, England, in 1969 and ultimately reintroduced to the African wild by conservationist George Adamson. One year after Adamson released Christian to the wild, his former owners decided to go looking for him to see whether Christian would remember them. He did, and with him were two lionesses who accepted the men as well.” – Wikipedia