Breakthrough: The Ideas That Changed the World

S1 E6 | CLIP

Polybius Square

Polybius, a Greek statesman and tutor to the Roman general, Scipio Africanus, sees that the Romans' method of signaling on the battlefield is limited to a small number of messages. He decides to invent a code so words can be exchanged between battalions freely. The result: the first long distance messaging system.

AIRED: May 22, 2019 | 0:01:42

- Convinced there must be a better way

to communicate over the battlefield,

Polybius comes up with the ingenious way

of using a code to indicate individual letters.

(playful symphonic music)

He comes up with a numerical grid

that enables every individual letter in the alphabet

to be identified by just two numbers.

It was a system known as the Polybius square.

The Roman signaler would begin by raising his torch

and waiting for the person

who would receive the message to acknowledge him.

Once he knew he was ready,

he would begin to spell out his message,

bit by bit, using Polybius's square.

So the first letter is P, it's five torches on the left

and three torches on the right.

Letter by letter, the signaler could spell out his message.

(fire crackling)

Next letter we've got is R,

two on the left and four on the right.

Polybius's signaling system,

was a revolution in military communication,

and sending messages over long distances.

(moves into faster paced music)

(soldiers shouting) (swords clanking)

- [Patrick] Polybius, had invented the first

two-way encrypted messaging system.

(flames roaring) (slow somber music)

But signaling this way was only possible by line of sight.

for the next 2000 years,

communicating further afield meant sending a letter.

And it was the tragic contents of a letter

that triggered the next step in the story of the smartphone.