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Secondary sourceArtifact

Heron's Automatic Temple Doors

Unknown

A diagram of Hero's mechanism for opening temple doors automatically using fire, heated air and water, described by Hero in the 1st century.

Illustrates a device Hero himself described, showing his use of fire and water to create seemingly miraculous effects.

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Engraved line drawing of Heron's automatic temple door mechanism. An altar with smoke rises on the left, connected by pipes and a water vessel to a pair of tall double doors on a temple facade on the right, with a pulley and weight below.
Diagram of Hero of Alexandria's automatic temple doors, 1st century design.

About this source

What it is

This engraving illustrates a mechanism described by Heron of Alexandria in the 1st century for opening temple doors automatically. The drawing shows an altar with rising smoke connected by pipes and a water vessel to a pair of temple doors, worked by a pulley and weight.

Why it matters

This device shows how Hero combined fire, air pressure and water to create effects that seemed magical in religious settings, impressing temple visitors with 'miracles'. It reveals the practical cleverness of ancient Alexandrian engineering and its link to both science and religious spectacle.

Look closer

  • Why might temple doors that open 'by themselves' have been powerful for ancient worshippers?
  • What basic physical principles does this device rely on?
  • How does this diagram, made later, try to represent Hero's original description?

This artifact is part of the curated material that grounds the AI version of Hero of Alexandria on Humy.ai — when students ask about related events, the AI can quote it and cite it.

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Manuscript page with Greek text in brown ink at top and bottom, and colored line drawings in the middle showing Hero's hydraulic bird-singing apparatus: several birds perched on pipes and arches, a tall cylindrical water vessel, a horizontal tank, and a bell-shaped weight on a chain.Book

Secondary source

Pneumatica

Hero of Alexandria · 1st century AD (this copy later)

Page from a Greek manuscript showing a colored line drawing of a temple-like structure with columns, arches, and a dome-like roof, with hidden tanks and mechanisms below. Greek handwritten text fills the lower part of the page.Book

Secondary source

Automata (Bacchus diagram)

Hero of Alexandria · 1st century AD (this copy later)

Painted miniature from a Greek manuscript: a bearded man with long grey hair in a golden-brown cloak extends his right hand toward the left, beside a dark archway. Red Greek lettering reads 'ΗΡΩΝ ΦΙΛΟΣΟΦΟ' beside him.Painting

Secondary source

Hero of Alexandria in the Codex of Saint Gregory Nazianzenos

Unknown author · 9th century AD

Illuminated manuscript page with colored design drawing of a large siege engine or cannon in red, blue, green and tan, with a vertical arrow-like beam at top, surrounded by Greek text in brown ink on parchment.Document

Secondary source

Belopoiika (design drawing of a siege engine)

Hero of Alexandria · 1st century AD (this copy later)

Title page of a 1589 Italian book, engraved in black and white with an ornate architectural border of columns, scrolls and a central medallion. Printed text reads Di Herone Alessandrino De gli automati, ouero Machine se moventi, libri due, tradotti dal greco da Bernardino Baldi, with a small shield reading In Venetia, appresso Girolamo Porro, 1589.Book

Secondary source

De gli automati, ouero Machine se mouenti

Hero : Alexandrinus · 1589

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