One of the biggest feats of Roman ingenuity lies in Lebanon’s historic Bekaa Valley, home to the ancient city of Heliopolis, now Baalbek. Here, the 2,000-year-old Temple of Jupiter was built on top of three colossal stones known as the Trilithon, or the Three Stones, and sits adjacent to the Temple of Bacchus. Not far from these mighty temples, within the limestone quarry from which the Trilithon originated, lie three more immense stones, the Stone of the Pregnant Woman, the Stone of the South and the Forgotten Stone.

Half buried in earth, as if moved and then forgotten by Roman builders at Baalbek, these massive stones have left archaeologists with a number of unanswered questions. They remain some of the biggest stones ever moved by human hands and were presumably intended to form the base of these temples. But how and why did the Romans transport these stones from the quarry? And, what ancient structure could have possibly required such enormous stones, anyway?

Quarrying the Stone of the Pregnant Woman
The Stone of the Pregnant Woman, known as Hajar el-Hible in Lebanon, was actually the first to be “discovered” as it was never fully buried underground. The huge megalith weighs about 1,000 tonnes (1,102 tons), and measures 20.76 by 4 by 4.32 meters (68.1 by 13.1 by 14.1 ft).

The Stone of the South was discovered in the 1990s in the same location, and weighs 1,242 tonnes (1.369 tons).

While it’s hard to imagine misplacing something so large, in 2014 archaeologists from the German Archaeological Institute found a sixth megalithic stone within the same quarry, right next to (and under) the Stone of the Pregnant Woman. They named it the Forgotten Stone . Measuring a staggering 19.6 by 6 by 5.5 meters (64 by 20 y 18 ft), it is estimated to weigh about 1,497 tonnes (1,650 tons). To put that into perspective, it’s the equivalent of 1,496,850 kilograms (or 3,300,000 pounds), making it the largest known stone ever quarried.

One of the biggest questions archaeologists have attempted to answer is how the Romans, who lacked advanced machinery, transported stone slabs of such immense size? More importantly, how did they extract such huge slabs of stone from the quarry in the first place?

There is archaeological evidence from all over what was the Roman Empire , of Romans extracting huge sections of rock for their structures. It was common to cut out a large piece of rock and then cut it down to size afterwards. One of the most common methods used relied on chalk lines and wedges. In order to cut the rocks from the quarry, an outline would have been created on the rock face, roughly the shape and size needed.

The outline would be created with chalk, and sockets for wedges would be inserted following these chalk lines. With a chisel and a mallet, wedges would be placed into these holes. In a technique reminiscent of the Rapa Nui and their moai statues , on making Roman monoliths at Baalbek, little pinpricks would be made along the line to encourage breakage along the marked lines. When the middle wedge was struck with a blow from a mallet the rock would open.

The stone would then be transported to the site. The German archaeologist Margarete van Ess has argued that the blocks were properly cut the same way as the masonry used for the Pont du Gard , a Roman aqueduct in France. If we assume that the stones were extracted in such a way, how did the Romans then transport these colossal pieces of stone all the way to the building site?

Transporting Megalithic Stone at Baalbek
There is evidence, not only from this site at Baalbek but from many others across what used to be the Roman Empire, that Romans were able to move heavy building materials, like these stones. In fact, there is proof from other ancient civilizations that humans were transporting heavy materials intended for all kinds of structures. Think of Stonehenge in England or the Pyramids in Egypt.

There are a few methods that ancient builders could have relied on for transporting these colossal stones. In the case of the Trilithon, however, many archaeologists argue a pulley system was used, although there is some controversy in academic circles.

A ninth century BC Assyrian relief provides evidence of this method being used, while some have argued the system was used by the Greeks in masonry in the late 7th century BC. The earliest concrete evidence comes from Aristotles’ Mechanical Problems , written in the early third century BC by the ancient Greek philosopher and polymath.

J. J. Coulton argued that this was a theoretical description of a system which had already been used by builders at the time. In an article entitled “Lifting in Early Greek Architecture”, Coulton claimed that builders had probably been using this system for three centuries or more by the time Aristotle recorded it in his work.

The limestone quarry from which the Trilithon originate lies 800 meters (2,624 feet) from the site where they now lie and is slightly higher up than the land on which the temples stand. This made moving these massive stones even harder. Evidence gathered from archaeologists’ observations of the stones on site implies that, once carved, the stones were placed on rollers.

To transport them to the site, capstans (a revolving cylinder with a vertical axis) were attached to pulley blocks on both sides of the load. The enormous stones were then slowly transported to the site. In order to operate these machines, 32 men were required, and to move enough stone, 16 machines were needed. This meant that a total of 512 men who could develop the power of more than 10 tonnes (11.02 tons) were required to move the stones.

As well as pulling extremely heavy loads along the ground in order to transport them, there is evidence from elsewhere of such methods being used to lift heavy loads. When combined with a winch, the pulley system created a type of crane. Vitruvius, the Roman architect and engineer, describes the mechanism clearly:

“Two beams are required for the jib, their thickness depending on the maximum probable load. They are fixed together at the top with an iron bracket, and separated at the base, like an inverted V. Ropes are attached to the head of the jib, and arranged “all around” to keep it steady. A pulley block is suspended from the top.”
Vitruvius’ account is also confirmed by surviving Roman depictions of such a mechanism. For example, a terracotta relief found on the Via Cassia, a Roman road which runs through Italy, depicts two workmen operating a winch.

Another similar machine can be found in the painting at Stabiae, an ancient city located near Pompeii. Again, in this piece of art, two men are shown to be operating the winch which transports a heavy, rectangular block held by a hook. Such cranes could easily be dismantled and transported to sites when needed, however, the legs of the crane needed to be firmly anchored to the ground. This meant that they couldn’t be used on raised or uneven surfaces.

Whilst this system was not used at Baalbek, it is demonstrative of the methods ancient builders relied on to move extremely heavy building materials and of how tried and tested methods could be adapted for different building environments.

Why Transport Enormous Roman Megaliths?
Archaeologists have also been preoccupied with understanding why these enormous stones were transported to the temples in the first place, and under whose orders. To answer the question rather simply, it has been assumed that the stones were moved in order to create the large platform on which the temples were built. The stones had to be so big because the karst topography of Baalbek demands strong foundations. The temples planned for the site were simply so vast (the Temple of Jupiter was the largest in the Roman world) that the stone slabs also had to be colossal to ensure the foundations were strong enough to bear the load.

There is no doubt that the Romans were not shy about moving large pieces of stone on this site specifically. The pillars of the Temple of Jupiter are also enormous. There were originally 54 of them, ten in the front and back of the temple and an additional nineteen along each side. Each pillar stood at 19.9 meters (65 ft) in height making the temple the tallest of any classical temples. The apex of the roof is estimated to have been a staggering 44 meters (144 ft) from the floor of the court. Whilst only six still stand today, they remain as an imposing reminder of just how big the temple would have been when completed.

Unfortunately, there is a lack of documentation in regard to who commissioned and paid for the temples themselves, as well as who designed the structures. It is believed that the temples were built here as part of a prehistoric Sun Temple. Many argue that the Greeks called the temple Heliopolis which means “Sun Temple” or “Sun City,” however, it is this uncertainty which has led historian Dell Upton to describe the site as a metaphor for the way imagination can distort the truth in architectural history.

Imagination Distorting the Truth in Architectural History
He writes that Baalbek has become “a very accommodating screen upon which to project strikingly varied stories.” But for the majority of non-professional history lovers, this is what makes such sites so fascinating. The kind of questions that sites such as Baalbek elicit are what really draw people into the story of an ancient monument or structure.

The 19th-century Scottish explorer, David Urquhart, felt this way. Upon seeing the stones, he stated he was “paralyzed” by “the impossibility of any solution.” He then went on to devote several pages of his diary to the “riddles” these stones posed, stating that they were “so enormous as to shut out every other thought, and yet to fill the mind only with trouble.”

Urquhart eventually came to the conclusion that the temples must have been built by contemporaries of Noah using the same technological expertise that facilitated the construction of his famed Noah’s Ark . The stones appear to be abandoned because, according to Urquhart, work on site had to be stopped with the coming of the flood.

In addition to Urquhart’s musings about Noah and the flood, there are many local legends about the origin of the site and its megaliths. Some argue that giants built the temples under the command of Nimrod, a biblical figure mentioned in the Book of Genesis and Books of Chronicles, and that the structure was called the Tower of Babel .

Some say Cain, the biblical figure mentioned in the Book of Genesis, built the structure to hide from the wrath of God. Others say Solomon, the King of Israel in the Old Testament of the Bible, built it with the assistance of djinns as a palace for the Queen of Sheba and that the stones are located where they are today because they were abandoned when the djinns went on strike.

More specifically, some argue that the Stone of the Pregnant Woman gained its name from a pregnant woman who tricked the people of Baalbek into believing she knew how to move the stone and promised to share the information if they fed her until she gave birth. Others have argued that the name comes from the legend that pregnant djinns were tasked with cutting and moving the stone. Finally, some say the name is a reflection of the belief that a woman who touches the stone supposedly experiences an increase in fertility.

As historians and archaeologists uncover more about the nature of the breathtaking site at Baalbek, there is no doubt that its long history tells a story of ancient technological ingenuity and advancement. What remains of the site, in the form of the towering pillars of the Temple of Jupiter or the imposing Stone of the Pregnant Woman protruding from the ground as if demanding to be seen, is a very literal depiction of what the Romans managed to achieve across their Empire. There is consistent evidence that they were able to transport and use these large pieces of stone in many of their buildings, even though we sometimes may not completely understand their methods or motives.

Top image: The Stone of the Pregnant Woman at Baalbek quarry. Source: Lodo27 / CC BY-SA 3.0