The first continuous as well as the first endless chain drive was originally depicted in the written horological treatise of the Song Dynasty by the medieval Chinese polymath mathematician and astronomer Su Song (1020-1101 AD), who used it to operate the armillary sphere of his astronomical clock tower, which is the first astronomical clock, as well as the clock jack figurines presenting the time of day by mechanically banging gongs and drums. The chain drive itself converted rotary to reclinear motion and was given power via the hydraulic works of Su's water clock tank and waterwheel, the latter which acted as a large gear.