In China, at the time working as a professional mining engineer, future President of the United States, Herbert Hoover and his wife were civilians under siege at the foreign legations' compound. The future first Lady, Louise "Lou" Henry Hoover, collected shrapnel from Boxer artillery that is on display at the Presidential Library in West Branch, Iowa. The Hoovers picked up Mandarin Chinese while in China and used it at the White House when they didn't want to be overheard.
Charlton Heston's character, Major Matt Lewis, was loosely based on the real-life officer in charge of the marine guard at the U.S. Legation, then Captain, later Lieutenant General, John Twiggs Myers USMC (1871-1952). Myers was in the forefront of some of the toughest fighting in the besieged legations, wounded during the fighting on the Tartar Wall.
During the opening scene where the Legations and their flags are displayed, the camera lingers on the Spanish flag for a few seconds. Given the fact the Spanish legation or diplomats are not mentioned in the movie, some have commented the flag is only shown as the film was filmed in Spain during Franco's regime. While this explanation probably has some truth, there was in fact a Spanish legation and diplomatic staff in Peking during the siege. However, like the Dutch and Belgian Legations, they had no marines and played little role in the siege. This is why "eleven foreign powers" are referenced but only eight nations are named.
The film, which was shot in Spain, needed hundreds of Chinese extras, and the company sent scouts throughout Spain and the rest of Europe to hire as many Asiatic-looking actors as they could find. The casting web in 1962 reached as far as London, Lyon and Marseilles, so the result was that many Chinese restaurants in those cities closed for the summer 1962 during filming because the restaurant staff - often including the restaurant's owners - was hired away by the film company. The company hired so many that for several months there was scarcely a Chinese restaurant to be found open in Spain and those 3 other cities.
Due to mainland China's hostility and isolation from the Western world, a full-scale 60-acre replication of Peking 1900 (sewers and all) was built in the plains outside Madrid, and Chinese/Asian extras were flown in from all over Europe to provide the local Peking (the old name of Beijing) citizenry. A number of costumes for the Royal Chinese Court (the Empress, Prince Tuan's, etc.) were authentic ones from Tzu Hsi's actual court. They were loaned by an illustrious Florentine family (which wished to stay anonymous) but was able to rescue them from the collapse of the dynasty right after the Boxer rebellion.
The production was troubled almost from the beginning. It ran into financial troubles, there were conflicts among the cast, and director Nicholas Ray argued so violently with producer Samuel Bronston that he eventually walked off the set and quit the picture, and soon afterward suffered a severe heart attack. Andrew Marton and Guy Green finished directing the picture, uncredited.
It is still possible to walk around the area of Beijing which was the actual location of the Siege of the Peking Legations in 1900, and to recognize sites and street layout depicted with admirable accuracy by the sets constructed in Spain for '55 Days At Peking'. The former legation quarter is east of Tiananmen Square, bounded in the north by Changan Avenue and south by Qianmen Street. One such important site is the gate of the former British Legation in Zhengyi Road, looking remarkably as it did in photos taken in 1900. Much of the area has been occupied for many years by Chinese Government agencies. Most of the heritage buildings remaining of the old legation quarter are reconstructions after the Boxer uprising. The area's tourist potential has been little exploited. The post-Boxer former French Legation post office is the foyer of the Dongjiaominxiang Hotel. The site of the former U.S. Legation has been renovated for up-market restaurants, bars and event venues.
The siege of the Peking Legation Quarter was a great backdrop for dramatic effect and story-telling as the basis of this movie because it involved so many nationalities and personalities through a real crisis in an exotic location. Some survivors of the Legations, however, felt they did not have as tough a time as those caught three miles away in the concurrent more closely confined siege by Boxers and soldiers of Peking's Northern Cathedral. Defended by only 25 French and 15 Italian marines, the Catholic Bishop Pierre-Marie-Alphonse Favier (1837-1905) held out for 56 days against sniping, bombardment and mining, losing 10 of his marines killed and 500 of his Chinese congregation. There is enough material in the cathedral siege for a movie in its own right.
Charlton Heston stated that his working relationship with Ava Gardner was very bad due to Gardner's unprofessional behavior during filming. She was very difficult to work with. Heston greatly enjoyed working with David Niven.
The cameraman on the film was originally going to be Aldo Tonti, but when he saw the sets already built at the Bronston studios, he claimed it would be impossible for him to photograph them in the way Nicholas Ray wanted. Jack Hildyard replaced him as director of photography only a short time before shooting began.
The Japanese Colonel Shiba, played by Jûzô Itami, is the only major character among those depicted in the besieged legations who has the real name of a key participant in the actual historical events. Shiba Goro (1860-1945), then with the rank of colonel, was military attaché at the Japanese Legation. The real life Colonel Shiba emerges as a true hero and the most admired military leader within the legations in contemporary newspaper accounts and memoirs, including by English and American authors. Wikipedia has an interesting article about his career.
Charlton Heston and David Niven brought in their own screenwriters to beef up their characters (the long sequence where they blow up a Chinese armory was added so Niven's character seemed more heroic).
Charlton Heston later recalled that during filming his chauffeur was not being paid by the production company. Heston twice confronted one of the producers about this and twice he got a very elaborate and flamboyant show of outraged indignation from the producer screaming over the phone at someone else, but the chauffeur was still not paid for his work. This annoyed Heston so much that he personally paid the chauffeur himself, and when he confronted the producer over it the producer then handed over enough money to reimburse Heston.
4,000 extras were required for the film, including Chinese people brought from restaurants and laundries across Europe since there were not enough available Chinese people in Spain for the mass scenes.
In the 1961 movie "The Guns of Navarone". David Niven is an explosives expert who comes up with the way to blow up a German powder magazine. Proving to Gregory Peck he is a knowledgeable demolitions man. In "55 Days at Peking" (1963) he goes along on a raid to blow up a magazine. And is shown how to do it by Charlton Heston.
In his diaries, Charlton Heston remarks that the the set was so large, that he recommended to producer Samuel Bronston that he should let Orson Welles use it to film a spy thriller simultaneously. Apparently there were portions of the set were never used during filming.
Apparently producer Samuel Bronston had commenced building sets for his Fall of the Roman Empire in 1961, and had his proposed star Charlton Heston visit the construction. On arrival Heston stated that he would be keener on a Boxer Revolution epic so the Roman sets were torn down and work now begun on building a brand new Peking backlot in the outskirts of Madrid.
The movie was filmed in Technicolor and Technirama, which involved the horizontal use of 35-millimeter film, resulting in 70-millimeter printed film format. The aspect ratio was 2.20:1, with the image viewed at 2.35:1 on 35-millimeter prints.