The book of games commissioned by the Spanish king Alfonso, dating from 1283, is the oldest source describing draughts. Information about draughts from earlier times is more fragmented. Will it in spite of this be possible to find where and when the long doubleton was invented? An effort based on linguistics.
Two medieval draughts varieties
In chapter 7 we have met with two varieties: a variety with a short king played in England and Italy, in earlier times also in France, and a variety played with a long king in countries like Spain, Turkey and Bahrain. Observation: cultures within the Roman sphere of influence had (have) a short king, cultures within the Arab sphere of influence a long king.
In the Middle Ages, the Roman and Arab variety each had its own name. Romance (French merelles, Italian marella, Spanish marro) had a game name derived from the Latin word marrus; Arabic dialects (for instance Moorish/Spanish alquerque) a game name derived from the Latin word calculus. Click here for my defence of this claim. These two names meant, among others, both 'draughts' and 'morris', click here and here for evidence. Which name is the older one? Probably the name going back to the word marrus: draughts played with the long king seems an improved version of the game played with the short king.
Can we find out where and when the long king was devised? I shall discuss two claims.
First claim: the long king is a Roman invention
I sketch the following scenario. Latin speaking people played draughts and morris under a name derived from the Latin word marro, for instance ludus marrelarum or a cognate form. Their draughts variety had a short king. Some day, the short king was replaced by a long doubleton. This new variety was called ludus calculorum or a cognate form, derived from the Latin word calculus. An Arab tribe borrowed this variety together with its name in the 7th c. or earlier: there are references of the Arabic game name querque (or a variant) from the 7th c. AD [Murray 1916:14-17, 1952:37].
This reconstruction contains two weak points.
First weak point. It is less plausible that the game with the long king received a new name, the game kept its main character. In such a case the human being does not think up a new name. Click here for more information about this naming principle.
Second weak point. That the new variety received a new name is rather implausible because of the fact that morris would have received a new name too -unless draughts was a much more prominent game than morris.
For these two objections the claim that the long king was an invention in a culture within the Roman sphere of influence is not plausible -at least not in my eyes.
Second claim: the long king is an Arab invention
A scenario in which I don't see any weak point: an Arab tribe borrowed draughts from a Latin speaking tribe together with its name; the Arab tribe dropped its own name for the game. It seems plausible this happened before the 8th c. AD, when the Moors started to subject the Iberian peninsula. The long king is indigenous Arab, and must be an invention in a central Arab region.
The two different Latin names for draughts
A last question: how to explain two different Latin names for the same thing? In the concrete: can I explain two Latin names, ludus marrelarum and ludus calculorum, for morris and for draughts with the short king? My reply: we must assume that inhabitants of some unknown Latin speaking regions called draughts ludus marellarum or a cognate form and that inhabitants of other regions called the game ludus calculorum or a cognate form. This is a frequent phenomenon. Open a dialect atlas and you'll find many different names for the same thing, always for objects, animals or tools occurring in the immediate surroundings. That draughts and morris had two different names means that these board games were very common, deeply rooted in the society -and for this reason ancient.
Playing Arab draughts in Spain, 13th c., with a long king