In Ancient Greece, several natural energy resources were in use, like the human and animal power, wind energy (e.g. in sailboats), thermal power (e.g. in metallurgy) and hydrodynamic energy (e.g. in clothes’ cleaning). An important change however was achieved during the Hellenistic period by converting natural energy resources, into kinetic motion, such as the water-driven bucket chain of Philon, the windmill-powered devices of Heron and the primitive steam-turbine of Heron. This advance made several mechanical applications feasible.