The Stockholm Olympics were held in July, 1912, the fifth Olympiad of the modern era.
But there was also a Stockholm Olympics in June, 1956, and only equestrian events were held at this particular event. Why? Because the actual host of the 1956 Olympiad was Melbourne, and Australia is famous for its tight quarantine control, a custom that goes back decades.
According to Wikipedia, Australia “had a strict six-month pre-shipment quarantine on horses,” and authorities insisted from 1953 that they would not allow horses enter Australia, even for the Olympics, which were to be held four months later, from November 22 to December 8. So, in 1954, the IOC decided that instead of cancelling the equestrian events, they moved them to Stockholm, Sweden instead.
As a result, the 1956 Olympiad was the first and last to be held in two different hemispheres in the same year, and 1956 saw posters that featured two different cities. The one above is the equestrian part of the 1956 Olympics in Stockholm, while the one below is the standard poster for the Melbourne Games.
Interestingly, Sweden won gold in half of the equestrian events: individual dressage, team dressage and individual eventing. One might think home field advantage made the difference. Maybe it did, although Sweden dominated the equestrian events at the 1952 Summer Olympics in neighboring Helsinki, Finland.
As is explained in the book, Success and Failure of Countries at the Olympic Games, by Danyel Reiche, success in equestrian events is directly correlated to a nation’s GDP – “Out of the 419 Olympic medals, 329 (78.5%) in equestrian were won by wealthy countries with a GDP above US$30,000.” In addition, Reiche points out that in the case of Sweden, “equestrian sports is a ‘folk sport’,” which may explain why Stockholm was selected as the venue on such short notice.