I can't believe the number of folks who miss the point of Anna And The King Of Siam in just dismissing it as typical western racism. Yes it's there, but the real story of Siam later Thailand is how it missed being colonized by the west. In that regard the story is like Japan.
King Mongkut who ruled from 1851 to 1868 and played by Rex Harrison in his first role in a Hollywood film, was a man who's sole ambition was to keep his country away from colonial hands. But he also knew that the west had far outstripped the east in material progress if not culturally. His challenge was to learn from the west without being taken over by them.
Toward that end he did import among other things Anna Leonowens, shortened to Owens in this film and played by Irene Dunne. Her job was to educate the royal children, most especially the Crown Prince Chulalongkorn who would rule Siam as Mongkut's successor. How much and what kind of personal relationship she developed with the King is part true and part from the fertile mind of Margaret Landon who wrote the book this and The King and I were based on.
Today when you visit Thailand they will tell you up front about how proud they are that they were never colonized by a western power, a singular achievement in the 19th century. They did give up chunks of territory, to the French in Indo-China, to the British in Burma and Malaya, but Siam was kept in being. Ironically enough when it was conquered it was by another Eastern power, Japan in World War II. Thailand most people forget because of that was an Axis power nation, quite unwillingly, but they had little choice in yielding to a nation that learned the lessons Mongkut and Chulalongkorn learned far better.
Giving good performances in the supporting cast are Linda Darnell, Lee J. Cobb, and Gale Sondergaard. Darnell's character as Tuptim, current favorite of the king has far more bite to it and she's not a nice girl who the western schoolteacher is trying to help on the path to true love. Cobb's role as the chief minister, the Kralahome is far more expanded in this than The King And I. And Gale Sondergaard as Lady Thiang, mother of the crown prince is touching as the mother who really does live for her son as she's got nothing else really in the world. She was nominated for Best Supporting Actress in 1946, but lost to Anne Baxter in The Razor's Edge.
It's also ironic that while any number of folks might decry the racism shown by whites in Anna And The King Of Siam, at the same time they're also revolted by the position of women in Siam, being not above household furniture. Irene Dunne's character is hardly a Victorian feminist, but just the contrast to the other females in the cast forces here to become one. But that was their culture and still is in many areas of modern Thailand.
The highly acclaimed remake of this story that starred Jodie Foster and Chow Yun Fat in 1999 tells far more of the real story. It's good to compare the two. The differences in both versions tell a lot more about us as a society than even about 19th century Siam.