Why you need to read about this historic, real-world puzzle after watching Tenet

Christopher Nolan loves confounding his audience. Perhaps none more so than in Tenet, which is now out on home release worldwide. Like much of his work, it helps to do some wider reading to understand the method behind the madness – especially when it comes to the Sator Square, an ancient puzzle that unlocks some hidden meaning in the time-bending epic. Below, we take a look at its history, what it is, and why it can help you better understand Tenet.

We've already done a spoiler-filled deep-dive explaining the Tenet ending, too, should you want to straighten out a few things.

SPOILER WARNING! Do not read on unless you have seen Tenet – we are going into major spoiler territory.

Still here? Then you have witnessed the mind-boggling movie that is Nolan's Tenet. We won't go into the logistics of the plot, but we want to talk about a Latin word square known as the Sator Square. The earliest example of this square was found in the ruins of Pompeii. But what is it?

Well, the Sator Square is comprised of five words which, when arranged in the right order, can be read from right to left, left to right, top to bottom, and bottom to top. The five words are SATOR, AREPO, TENET, OPERA, and ROTAS. Here's an example of an early Sator Square.

The Sator Square

Recognise those words? Well, the most obvious, and central, is the title of the movie, TENET, a palindrome – a word that can be read the same forwards and backwards – that also has multiple meanings. Tenet becomes the name of The Protagonist's (John David Washington) organisation and is also "ten" backwards and forwards. The final mission of the movie, of course, was 10 minutes backwards and forwards. What!

Now, the other four words also all appear throughout Tenet. SATOR is the name of Kenneth Branagh's villain. The security company Sator hires is called ROTAS Security, another one of the words. ROTAS also ties in with the machines that invert people; the Latin words Rotas means wheel, and the machines are weird turnstiles that are sort-of wheels into becoming inverted/un-inverting yourself. 

OPERA is perhaps one of the more obvious words, as the opening scene takes place at an opera house and The Protagonist convinces Sator to trust him by asking whether he likes opera. The final word is AREPO, which is the name of the man who creates the fake Goya paintings that Elizabeth Dikicki's Kat accidentally claims are real, leading to her husband Sator having a hold over her.

So, why did Christopher Nolan do this? Why relate the movie to the Sator Square? Well, it all has to do with our idea of time and inversion. Where the words in the square can be read backwards and forwards, so, too, do things happen backwards and forwards in Tenet. 

This is just one of the many wonderful small details that will have you talking about Tenet for years to come. Read more spoiler-filled analysis here.