The common use of armorial bearings, and the practice of the tournament, may be Oriental in their origin; the latter has its affinities with the equestrian exercises of the Jerid, and the former, though of prehistoric antiquity, may have received a new impulse from contact with the Arabs.
One branch extends northwards up this frontier and north-eastwards across the central Tunisian table-land, and the other continues south-eastwards between Gafsa and the salt lakes of the Jerid.
They are smooth depressed areas (in the case of the largest, the Shat el Jerid, lying a few feet below the level of the Mediterranean), which for more than half the year are expanses of dried mud covered with a thick incrustation of white or grey salt.
It would seem probable that at one time these shats (at any rate the Shat el Jerid) were an inlet of the Mediterranean, which by the elevation of a narrow strip of land on the Gulf of Gabes has been cut off from them.
All this region round the shats has been called the "Jerid" from the time of the Arab occupation.