The idea using the power of steam is quite old. A Greek mathematician and engineer who resided in the Ptolemaic Egypt, named Hero, wrote a manuscript describing various devices and ideas of the time. Although it is not sure that Hero was the inventor of these devices, he is credited for the earliest mention of steam power. Hero describes a method to open the doors of a temple with the action of a fire on an altar at the front of the temple. A series of pipes runs between altar and the temple doors: it is the steam created by the fire on the altar and the suitable syste of pipes to open the temple doors.