The origins of the medieval tournament are unknown, but it probably started as a practice for the cavalry. In the late Roman period [400s], there was a large number of cavalry that needed training, but if it became a festival at that time we do not know. The Franks were brilliant at cavalry and certainly had horse-related games, but if those games were related to military training is again not known. The first person to make rules for a tournament was Geoffroi de Preulli who weirdly died in a tournament in 1066. When do you think tournaments started?