Olympiad beginning on the opening of the Olympic Games for the summer sports. The first modern Olympiad began in 1896, the second in 1900, and so on (the 31st began in 2016: see the Olympic Charter). The ancient and modern Olympiads would have synchronised had there been a year zero between the Olympiad of 4 BC and the one of 4 AD. But as the Gregorian calendar goes directly from 1 BC to 1 AD, the ancient Olympic cycle now lags the modern cycle by one year. An ancient Olympiad was a period of four years grouped together, counting inclusively as
International History Olympiad assigned to teams for the team events at the Olympiad based on a number of factors, though every effort is made to keep students from the same country or state together. Teams consist of either 2 or 3 students. For team events, if a "mixed" team wins a medal, the medals are credited fractionally on the medals table depending on how many students from a state or country were on the team. After 2016, the Olympiad became a biennial model; Olympiads thus occur in even-numbered years. The location of the 2020 International History Olympiad has yet to be determined, though