We have 2 other sizes of the Roman biga (please see these other two listings). The Romans probably borrowed chariot racing from the Etruscans, who would themselves have borrowed it either from the Celts or from the Greeks, but the Romans were also influenced directly by the Greeks especially after they conquered mainland Greece in 146 BC. In the Roman Empire, chariots were not used for warfare, but for chariot racing, especially in circi, or for triumphal processions, when they could be drawn by as many as ten horses or even by dogs, tigers, or ostriches. There were four divisions, or factiones, of charioteers, distinguished by the color of their costumes: the red, blue, green and white teams. The main centre of chariot racing was the Circus Maximus, situated in the valley between the Palatine and Aventine Hills in Rome. The track could hold 12 chariots, and the two sides of the track were separated by a raised median termed the spina. Chariot races continued to enjoy great popularity in Byzantine times, in the Hippodrome of Constantinople, even after the Olympic Games had been disbanded, until their decline after the Nika riots in the 6th century.The starting gates were known as the Carceres. An ancient Roman car or chariot drawn by four horses abreast together with the horses drawing it was called a Quadriga, from the Latin quadrijugi (of a team of four). The term sometimes meant instead the four horses without the chariot or the chariot alone. A three-horse chariot, or the three-horse team drawing it, was a triga, from trijugi (of a team of three).