The Roman created and developed lots of interesting inventions. For example, they created concrete, underfloor heating, and the calendar that people still use today. But did they develop the steam engine?
The ancient Romans didn’t invent the steam engine as people know it today. Englishman Thomas Savery invented it in 1698. However, the Romans first discovered the potential uses for steam, and Roman engineer Hero (or Heron) of Alexandria (10-70 A.D.) built the first steam-powered machine, the Aeolipile.
This article will shed more light on the Aeolipile, also known as “the Roman steam engine,” and its inventor, Hero of Alexandria. It will also examine how the Aeolipile was used and talk a bit about the modern version of the steam engine.
Also see Did the Romans Lift Weights? to learn more.
Who Invented the Roman Steam Engine?
Greek mathematician, engineer, and inventor, Hero (sometimes called “Heron”) of Alexandria invented the Roman steam engine, also known as the Aeolipile. He also developed an early version of the syringe, a wind-powered organ, a stand-alone fountain, and a holy water-dispensing vending machine.
And those few things were only a handful of his many creations. Of them, the Aeolipile surprisingly wasn’t one of his most impressive inventions at the time.
Today, when most people think of steam engines, they picture trains and large boats, but the Roman steam engine was a much smaller invention, and ancient Romans viewed it as more of an eccentric amusement than something with practical value. 
Live Science has an excellent illustration of Hero’s Aeolipile, along with an accurate description of the device:
“Heron’s Aeolipile consisted of a hollow sphere, mounted on a pair of tubes. Heated from below by fire, the tubes transported steam to the sphere, where it was released through another series of tubes projecting from the sphere’s equator. This movement of steam through the device caused the sphere to revolve, demonstrating the potential for using steam as a means of propulsion.” 
Unfortunately, as mentioned above, Hero considered the device an amusing novelty and never actually did anything with it, which is why he isn’t usually credited as being the true inventor of the steam engine. As Popular Mechanics points out, his steam machine produced “negligible torque,” and what little torque it did have was ineffective. 
Also see Did the Romans Have Ice? to learn more.
Hero’s Other Inventions
Some of Hero’s other famous inventions include the following:
- Vending Machine: Hero created the first vending machines, which he installed in temples. Visitors to the temple could drop a coin into a slot on top of the devices (which probably looked a bit like modern-day gumball machines), and it would dispense a predetermined amount of holy water for the visitors to use.
- Automated Menagerie: This invention of Hero’s was created solely for entertainment. The menagerie contained moving dolls and puppets, and he used it to amuse people at the theater. He even “programmed” it to act out a ten-minute play.
- Syringe: This device was a primitive but very effective predecessor to the modern-day syringe doctors use today.
- Self-Refilling Wine Glass: The glass was attached to a larger container of wine via a pipe, and as people drank, the system would refill the glass to keep the wine at a constant level.
Also see Did the Romans Have Steel? to learn more.
What Was the Aeolipile Used For?
The Aeolipile had no practical use; its own inventor considered it little more than a toy designed to amuse the masses. However, Roman architect Vitruvius speculates in his book that it may have been intended as a way to explore and understand “the laws of the heavens” – i.e., clouds and weather.
The above-mentioned Popular Mechanics article states that it was likely used to “entertain and spark wonder” in anyone who saw it, furthering the idea that the invention had few — if any — practical applications.
Part of the problem, most people agree, is that it was an invention ahead of its time. When Hero created the Aeolipile, Rome was operating primarily on slave labor, and the common consensus was that there was no need for machines that made work easier when slaves were doing all of the work.
Some websites claim that Hero used a version of the Aeolipile to operate his automatic doors, but that’s not precisely the case. Hero did make the first automatic doors, but they didn’t open because of a steam engine. Instead, they operated on a water-based hydraulic system. 
There was always an altar beside the automatic doors used on temples. Priests would light a fire in the altar, setting into motion a complex water-based system beneath the altar. As the heat from the fire grew, the water beneath the altar would be displaced, and the weights (buckets of water) would move, causing the doors above to open.
Also see Did the Romans Have Paper? to learn more.
When Was the Modern Steam Engine Invented?
Thomas Savery invented the modern steam engine in 1698, though others used more primitive models before this time. The steam engines used before Savery’s inventions were based on Hero’s original design for the Aeolipile.
Savery created the modern steam engine to remove water from flooded mines. Jerónimo de Ayanz, a Spaniard who worked as a mining administrator, filed a patent for a similar machine several years earlier, in 1606. Still, Savery’s invention is the first to bear the name “steam engine.” Unfortunately, Savery’s invention was prone to explode on occasion.
As often happens with science, technology, and engineering, once one person comes up with something great, others soon begin tinkering with, using, and improving the original design. That’s precisely what happened with Savery’s steam engine.
In 1711, Thomas Newcomen improved Savery’s design and created a new version of the steam engine that was less likely to explode when it was in use. It was this creation that became “the first commercially successful machine that used steam to operate a water pump.”
This design remained in use for the next five decades before anyone made any further improvements to it, and people used it for more than simply draining flooded mines. Some of these other uses for the steam engine were as follows:
- It helped provide towns with a stable water supply.
- It was a crude energy source that, in conjunction with a water wheel, provided power to mills and factories.
- It enabled farmers and architects to drain swampy wetlands.
The Romans may have invented the first version of the steam-powered machine many years before Thomas Savery, but unfortunately, it had little practical use.