Researchers have claimed that the aliens people who built Stonehenge did so using Pythagoras’ Theorem, a good two millennia before he was born.

The claim was made in the new book Megalith: Studies in Stone, released yesterday to coincide with the summer solstice. Looking at the geometry of the stones that make up Stonehenge, they said they found evidence for this idea.

Pythagorean theory states that the square of the longest side (hypotenuse) of a right-angled triangle is equal to the square of the two shorter sides. It was devised by the ancient Greek mathematician Pythagoras in the fifth century BCE. Stonehenge, however, was built a good 2,000 years earlier.

“People often think of our ancestors as rough cavemen but they were also sophisticated astronomers,” John Martineau, a contributor and editor to Megalith, told The Telegraph. “They were applying Pythagorean geometry over 2,000 years before Pythagoras was born.”

The claims made by the researchers are that there is a rectangle of Sarsen stones in the Stonehenge circle (around the central stones) dating back to 2,750 BCE that, when split diagonally, forms a perfect Pythagorean triangle. The eight lines radiating from the rectangle and triangles apparently align with important dates on the Neolithic calendar, such as the solstices and equinoxes.

It’s probably worth noting at this point that this is a book, not a peer-reviewed paper, so take it with a grain of salt. Also, some of the eight authors have rather odd views along the lines of giants or aliens being involved in the construction of Stonehenge. So, yeah.

A lot of mysteries remain about Stonehenge, including how the stones were raised, and why they’re there in the first place. Was it really constructed with some fancy mathematics behind the scenes? It’s claimed that Woodhenge, near Stonehenge, was also constructed using Pythagorean theory.

“These days it’s seen as hippy-dippy or New Age, but actually it’s a colossal omission to the history of science that we don’t see these monuments for what they are,” Robin Heath, one of the authors, told Inverse.

“People see the Neolithic builders of Stonehenge as howling barbarians, when they were very learned and it has been forgotten.”