miḥrâb, with a doorway on either side, and the upper part is decorated with a row of flat trifoliate niches. In the centre of the castle a round minaret rises from a massive square base (Fig. 30). Towards the top of the minaret there is a double band of ornamental brickwork with a brick inscription between. I could not decipher the inscription, owing to its great height, but the characters were not Cufic, and the round shape of the minaret makes it improbable that it should be earlier than the twelfth century. Beyond the minaret is a vaulted cistern. The shelving north-west side of the hill is defended by a double ring of brick towers, but on the south-east side, where the rocks are precipitous, there is little or no fortification. The brick walls of the buildings above the gate-way are decorated with string courses and bands of diamond-shaped motives, the diamonds set point to point or enclosed in hollow squares (Fig. 32). The history of the castle is not easy to disentangle from the accounts left by the Arab geographers. An earlier name for it was Dausar, but even this does not seem to have been applied before the seventh century, though Idrîsî, writing in the twelfth century, ascribes its foundation to Alexander. He is the first author who mentions Dausar and he gives no authority for his statement as to its origin. Opposite Dausar, on the right bank of the Euphrates, stretches the battlefield of Ṣiffîn, where in A.D. 657 the Khalif ’Alî met the forces of the Umayyad Mu’âwiyah. Tradition has it that ’Alî entrusted his ally Nu’mân, a prince of the house of Mundhir, with the defence of these reaches of the Euphrates, and that a servant of the latter, Dausar by name, built the castle which was called after him. It took its present name from an Arab of the Ḳusheir, from whose sons it was wrested (in A.D. 1087) [Illustration: FIG. 29.--ḲAL’AT JA’BAR.] [Illustration: FIG. 30.--ḲAL’AT JA’BAR, MINARET.] [Illustration: FIG. 31.--ḲAL’AT JA’BAR, HALL OF PALACE.] [Illustration: FIG. 32.--ḲAL’AT JA’BAR, BRICK WALL ABOVE GATEWAY.]