No other legionary camps of the size of these three exist along the Arabian limes; the other fortresses which have been examined and planned are smaller, different in character, and later in date. Of these there are three which I propose to consider, Da’djaniyyeh, Bshair, and Qasṭal. Da’djaniyyeh is undated, but from its plan I should judge it to be earlier than the other two. Bshair is dated by an inscription in the time of Diocletian; for Qasṭal there is no epigraphic evidence, but the capital found among the ruins of the Sacellum can scarcely be earlier than the fifth century.[199] That the towers in the fortress of Da’djaniyyeh should be rectangular and set à cheval upon the walls, is not of any significance (Fig. 24). Round and square towers are commonly found at one and the same time, though the round tower, which is strategically an improvement upon the rectangular tower, is in fact later in origin (see below, p. 108). It is worth noting that the details of construction in the walls and towers of Da’djaniyyeh are exactly reproduced at Qasṭal, a fort which diverges much more than Da’djaniyyeh from the Roman camp scheme, but even at Qasṭal the stairs and approaches to the towers are copied from the Odhruḥ prototype. The remarkable feature at Da’djaniyyeh is that the Roman camp plan is obscured and almost lost. The greater part of the Intervallum is filled in with buildings; stables, horrea, and armamentaria are linked to the encompassing wall in a manner which recalls the ancient oriental system, a system which is perhaps foreshadowed at Ḍumair and Ledjdjûn.[200] In a wall set round with chambers there is no room for gates; the suppression of gateways is therefore a necessary corollary of the change of scheme, and at Da’djaniyyeh the Portae Praetoria and Decumana have disappeared. The postern in the south-east wall is not a survival of the Porta Praetoria; its existence is due to the fact that the main water-supply of the fort was a cistern lying outside the walls at this point. Apart from these striking innovations the interior preserves the Roman plan. The Praetorium and Sacellum stand in their accustomed place, but the Via Praetoria, besides having no independent gate, is no longer laid quite symmetrically with regard to the Praetorium. Something like the same combination of camp and oriental fortress can be seen in the Byzantine citadel at ‘Abdeh, but the features of the Roman camp are more completely obliterated and the Praetorium is probably represented by a large ruined building, placed unsymmetrically against one of the walls.[201] At Bshair the orientalizing process is carried a long step further (Fig. 25). The chambers are placed symmetrically round the enclosing wall; there is but [Illustration: FIG. 25. Bshair. (From _Provincia Arabia_, by kind permission of Professor Brünnow.)]