Who built Petra, and why? The Nabataeans, the Treasury, the water system and the theories

Architecture · 4 September 2026

Petra was built by the Nabataeans, an Arab people who controlled the caravan routes bringing frankincense, myrrh and spices from Arabia to the Mediterranean, and who made a hidden canyon in southern Jordan their capital from about the 4th century BC until the Romans annexed the kingdom in AD 106. Its famous monuments, the Treasury, the Monastery and some 800 tombs and temples cut straight into pink sandstone cliffs, were carved mostly between about 100 BC and AD 100, when the incense trade was at its richest. They are not what their names say: the Treasury is a royal tomb, and Petra was not a city of tombs but a city of 20,000 people, with markets, a theatre, a colonnaded street and a water system that made the desert bloom. Below: who the Nabataeans were, why they built here, what the Treasury is, how the water worked, the Bible and the Romans, the rediscovery of 1812, and a separate section for the theories.

The Nabataeans

They first appear in 312 BC, when a Greek army from Syria tried to seize their stronghold and its treasure of frankincense and silver and was beaten off; the historian Diodorus describes them as nomads who "neither sow nor plant" and hide their water in secret cisterns. Within two centuries they had a kingdom from Damascus to the Red Sea, a king, coins, an alphabet that became the ancestor of Arabic script, and a capital at Petra, Raqmu in their own language. Their wealth came from taxing and guiding the caravans of the incense road: a camel-load of frankincense from Yemen took two months to reach Gaza, and the Nabataeans controlled the wells and the tolls along the way, as well as the bitumen of the Dead Sea sold to Egypt for embalming. Their art mixed Greek, Egyptian, Mesopotamian and Arabian forms, which is why the Treasury looks like a Hellenistic temple with an Egyptian goddess on it. Nabataeans.

Why here

Petra sits in a basin of the Wadi Musa surrounded by sandstone mountains, reached from the east through the Siq, a gorge 0.75 miles (1.2 km) long and in places only 10 feet (3 m) wide. That made it defensible: a caravan could be seen for miles and stopped at the gorge. It lay where the incense road from Arabia met routes to Gaza, Damascus and the Gulf. It had springs, and the Nabataeans were the best hydraulic engineers of their age. And the rock was soft enough to carve and beautiful, banded in red, yellow and white, so that a facade could be cut from the cliff rather than built, which is why the city looks the way it does.

The Treasury: what it really is

Al-Khazneh, "the Treasury", is the first monument seen from the Siq: a facade 128 feet (39 m) high and 80 feet (25 m) wide, carved from the top down into the cliff, with two storeys of Corinthian columns, a broken pediment and a central round pavilion topped by an urn. Bedouin legend said the urn held a pharaoh's gold, and it is pocked with bullet holes from attempts to break it; it is solid stone. The building is a tomb, probably of the Nabataean king Aretas IV, who reigned 9 BC to AD 40, at the height of the city's wealth; excavations in 2003 found burials in chambers beneath the facade. The figures carved on it, the goddess Isis-Tyche in the centre, Amazons and Dioscuri, are Hellenistic, and the whole facade is a stage set of Alexandrian architecture in a canyon in Arabia. The inside is a single plain chamber. Al-Khazneh.

How the city was built and watered

• Carving. The facades were cut from the top of the cliff downward, so that the workers stood on the uncut rock below and never needed scaffolding; the ledges they left are still visible above some tombs. Iron chisels and picks; the surfaces were then dressed with diagonal strokes that catch the light.
• Building. The city centre was built, not carved: the Great Temple, the Qasr al-Bint temple, the colonnaded street, the theatre for 8,500 cut into a hillside, markets, baths and houses, many of them destroyed by earthquakes in 363 and 551.
• Water. Petra receives about 6 inches (150 mm) of rain a year, mostly in flash floods. The Nabataeans built dams across the Siq and the wadis to divert the floods, cut channels along both walls of the Siq carrying spring water in terracotta pipes, and dug more than 200 cisterns and reservoirs in the rock, lined with waterproof plaster, so that the city had water all year and the gardens had fountains. The system supported perhaps 20,000 to 30,000 people and is why the city was where it was.

The Bible, the Romans and the end

Petra is not named in the Bible, but the region is: it was Edom, and "Sela", meaning rock, in 2 Kings and Isaiah is often identified with it; the Nabataean king Aretas IV, the probable owner of the Treasury, appears in 2 Corinthians as the ruler whose governor tried to arrest Paul in Damascus. In AD 106 the emperor Trajan annexed the Nabataean kingdom as the province of Arabia Petraea without a fight, and Petra got a Roman colonnaded street and an arch, but the trade was shifting to sea routes and to Palmyra, and the city slowly declined. The earthquake of 363 destroyed much of the built centre; by the 7th century, after the Arab conquest, it was a village. The Crusaders held a fort there in the 12th century, and then the West forgot it until the Swiss traveller Johann Ludwig Burckhardt, disguised as a Muslim pilgrim, was led through the Siq in 1812. It became a World Heritage Site in 1985 and was named one of the New Seven Wonders in 2007; the Bedouin who lived in its caves were moved to a village in 1985.

Versions and theories

Everything below is a version, not a fact. These are the claims that appear in search next to "who built Petra", each with who made it and what the evidence says.

The Treasury holds treasure

Version. The Bedouin name and the bullet-scarred urn. Reply. The urn is solid sandstone, the chamber is empty and the burials found in 2003 were ordinary Nabataean tombs; the "treasury" was a royal mausoleum.

Petra was built by the Egyptians, or is in the Bible as the city of Moses

Version. The Wadi Musa, "valley of Moses", and the spring of Ain Musa, where Moses supposedly struck the rock, give the site a Biblical aura, and early travellers assigned the monuments to pharaohs. Reply. Every inscription, coin and pot at Petra is Nabataean or later; the monuments date from 2,000 years after Moses, and the Egyptian elements are borrowed decoration.

The Nabataeans were a lost or non-Arab people

Version. That the builders were some vanished civilization. Reply. Their names, gods and language are Arabian; their script became Arabic; and the Bedouin tribes of southern Jordan are their likeliest descendants. They did not vanish; they became Roman provincials and then Arabs like everyone around them.

It was carved with lost technology

Version. The precision of the facades is offered as proof of unknown tools. Reply. Unfinished facades at Petra show the process, cut from the top down in bands with chisel marks visible, and identical work survives at the Nabataean city of Hegra in Saudi Arabia with inscriptions naming the masons.

Petra was a purely religious or funerary city

Version. Because the visible monuments are tombs. Reply. Excavations since the 1990s have uncovered houses, markets, a pool and garden complex, a theatre and workshops; the tombs are on the cliffs because that is where tombs go, and the living city lay in the valley below.

What is in the archive

Al-Khazneh is in the Ancient temples of the world collection beside its Roman-period neighbours, the temples of Baalbek in Lebanon and the Temple of Hadrian at Ephesus, and the Egyptian temples whose gods the Nabataeans borrowed. For the other great rock-cut monuments, see Abu Simbel and the Kailasa Temple at Ellora.

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