# Hero of Alexandria

**Heron of AlexandriaHeroHeronHeron (or Hero) of AlexandriaHeron the ElderHerosOn the Dioptratechnology**

Hero of Alexandria (, Heron ho Alexandreus; also known as Heron of Alexandria ; c. 10 AD – c. 70 AD) was a mathematician and engineer who was active in his native city of Alexandria, Roman Egypt.wikipedia

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### Aeolipile

**firstHero's engine**

Hero published a well-recognized description of a steam-powered device called an aeolipile (sometimes called a "Hero engine").

In the 1st century AD, Hero of Alexandria described the device in Roman Egypt, and many sources give him the credit for its invention.

### Windmill

**windmillswind millwind**

Among his most famous inventions was a windwheel, constituting the earliest instance of wind harnessing on land.

Hero of Alexandria (Heron) in first-century Roman Egypt described what appears to be a wind-driven wheel to power a machine.

### Steam engine

**steam powertriple expansion enginetriple expansion**

Hero published a well-recognized description of a steam-powered device called an aeolipile (sometimes called a "Hero engine").

The first recorded rudimentary steam-powered "engine" was the aeolipile described by Hero of Alexandria, a mathematician and engineer in Roman Egypt in the first century AD.

### Pantograph

**eidographpantographicpantographs**

In his work Mechanics, described the pantographs.

The ancient Greek engineer Hero of Alexandria in his work Mechanics, describe the pantographs.

### Vending machine

**vending machinesvendingcoin-operated machine**

The earliest known reference to a vending machine is in the work of Hero of Alexandria, an engineer and mathematician in first-century Roman Egypt.

### Cybernetics

**cyberneticcyberneticiancybernetically**

Although the field was not formalized until the twentieth century, it is thought that the work of Hero, his automated devices in particular, represents some of the first formal research into cybernetics.

Although they considered this part of engineering (the use of the term cybernetics is much posterior), Ktesibios and others such as Heron and Su Song are considered to be some of the first to study cybernetic principles.

### Heron's fountain

Heron's fountain is a hydraulic machine invented by the 1st century AD inventor, mathematician, and physicist Heron of Alexandria.

### De architectura

**Ten Books on ArchitectureOn Architecturebooks of architecture**

The device is also described by Hero of Alexandria in his Pneumatica.

### Heron's formula

**Heron–Archimedes formulaHeron’s formula**

Today, however, his name is most closely associated with Heron's formula for finding the area of a triangle from its side lengths.

In geometry, Heron's formula (sometimes called Hero's formula), named after Hero of Alexandria, gives the area of a triangle when the length of all three sides are known.

### Greeks in Egypt

**GreekGreeksGreco-Egyptian**

Hero may have been either a Greek or a Hellenized Egyptian.

### Methods of computing square roots

**Babylonian methodreciprocal square rootBakhshali approximation**

Hero described a method for iteratively computing the square root of a number.

The method is also known as Heron's method, after the first-century Greek mathematician Hero of Alexandria who gave the first explicit description of the method in his AD 60 work Metrica.

### Musaeum

**MuseionMouseionMuseum of Alexandria**

It is almost certain that Hero taught at the Musaeum which included the famous Library of Alexandria, because most of his writings appear as lecture notes for courses in mathematics, mechanics, physics, and pneumatics.

### Ancient Discoveries

The program was a follow-up to a special originally broadcast in 2005 which focused on technologies from the Ancient Roman era such as the Antikythera mechanism and inventors such as Heron of Alexandria.

### Fermat's principle

**principle of least timeFermat's Principle of Least TimeFermat's optical principle**

Hero of Alexandria, in his Catoptrics (1st century CE), showed that the ordinary law of reflection off a plane surface follows from the premise that the total length of the ray path is a minimum.

### Automaton

**automataautomaticautomatons**

This tradition continued in Alexandria with inventors such as the Greek mathematician Hero of Alexandria (sometimes known as Heron), whose writings on hydraulics, pneumatics, and mechanics described siphons, a fire engine, a water organ, the aeolipile, and a programmable cart.

### Ctesibius

**Ctesibius of AlexandriaKtesibios**

Some of his ideas were derived from the works of Ctesibius.

Proclus (the commentator on Euclid) and Hero of Alexandria (the last of the engineers of antiquity) also mention him.

### Pneumatics

**pneumaticpneumaticallycompressed air**

It is almost certain that Hero taught at the Musaeum which included the famous Library of Alexandria, because most of his writings appear as lecture notes for courses in mathematics, mechanics, physics, and pneumatics.

The origins of pneumatics can be traced back to the first century when ancient Greek mathematician Hero of Alexandria wrote about his inventions powered by steam or the wind.

### Water organ

**hydraulishydraulic organearly**

Water organs were described in the numerous writings of the famous Ctesibius (3rd century BC), Philo of Byzantium (3rd century BC) and Hero of Alexandria (c.

### The Plot to Save Socrates

On her path she meets up with the great historic inventor Heron of Alexandria but soon realizes that not only is Heron a time traveler himself (from a future later than hers) but is a suspicious and ruthless character.

### Odometer

**clockingmilometerodometers**

Hero of Alexandria (10 AD – 70 AD) describes a similar device in chapter 34 of his Dioptra.

### Pierre de Fermat

**FermatPierre FermatFermat, Pierre de**

Hero of Alexandria later showed that this path gave the shortest length and the least time.

### Heronian triangle

**Heron triangleHeronianAlmost-equilateral Heronian triangle**

Heronian triangles are named after Hero of Alexandria.

### Heronian mean

**Heronian**

It is named after Hero of Alexandria.

### Catapult

**catapultsballistic devicesCatapelta**

The introduction of crossbows however, can be dated further back: according to the inventor Hero of Alexandria (fl.

### Dioptra

An entire book about the construction and surveying usage of the dioptra is credited to Hero of Alexandria (also known as Heron; a brief description of the book is available online; see Lahanas link, below).