The secret behind the Astragal game

During my last visit to the National Archaeology Museum in Naples, I was fascinated by a simple sepia drawing representing girls involved in a knuckle-bone or Astragal game. It was displayed with other smaller colorful frescos and this picture obviously stood out because of its fine lines. 

It was a plain tuf slab painted with delicate black and brown strokes dating from the 3^rd century BC and recovered from Egnazia in southern Italy. 

Initially, the knuckle-bones were designed for children and used just like dice having four sides rather than the usual six. 

It doesn’t look like a boy’s game but I am sure that it would have been familiar to Alexander. However, the secret is that these bones could also play a role to transmit secret messages as explained by Aeneas Tacticus.  This Greek writer, who Alexander must have been aware of, made headlines as being the first author to pen down a complete guide to securing military communications, including the best tactics to defend a fortified city. Also, the earliest hydraulic semaphore system is attributed to Aeneas Tacticus by Polybius. 

This means that this rather innocent toy could play an important role to send encoded messages. 

Earlier this year, Karawansaray Publishers shared an article on the subject and kindly quoted Aeneas Tacticus describing how to encode a message using these sheep bones. 

The most secret method of all for sending messages, but the most difficult, namely, that without writing, I shall now make clear. It is this. In a sufficiently large astragal bore twenty-four holes, six on each side. Let the holes stand for letters, and note clearly on which side begins Alpha and the following letters that have been written on each particular side. Then whenever you wish to communicate any word by them, draw a thread through them, as for instance, if you wish to express Aineian by the drawing through of a thread, begin from the side of the astragal on which Alpha is found, pass the thread through, and omitting the characters placed next to Alpha, draw through again when you come to the side where Iota belongs; and disregarding the characters following this, again pass the thread through where Nu happens to be. And again passing by the succeeding letters draw the thread through where Ei [the original name for Epsilon] is found. Now continuing in this way to write the rest of the communication, pass the thread into the holes in such a manner as that in which we just now wrote the name. Accordingly, there will be a ball of thread wound around the astragal, and it will be necessary for the one who is to read the information to write down upon a tablet the characters revealed by the holes. ... [to decipher the message (in reverse)] A piece of wood about 20 centimetres long perforated as many times as the letters of the alphabet, and the thread were then in the same way drawn into the holes. 

The marvelous drawing exhibited in Naples is a far cry from secret messaging as the ladies clearly enjoy their play. I was especially admiring the details of the lady at the bottom right in this picture. Not only are the folds of her dress standing out, but also the delicate line for her sandals and most of all her splendid long wavy hair!