functioned as an advance guard that could, in case of need, strike either west or east at the Sarmatians living at the borders. Therefore, the indefensible character of the province did not appear to be a problem for Trajan, as the province was conceived more as a sally-base for further attacks. Even in the absence of further Roman expansion, the value of the province depended on Roman overall strength: while Rome was strong, the Dacian salient was an instrument of military and diplomatic control over the Danubian lands; when Rome was weak, as during the Crisis of the Third Century, the province became a liability and was eventually abandoned. Trajan resettled Dacia with Romans and annexed it as a province of the Roman Empire. Aside from their enormous booty (over half a million slaves, according to John Lydus), Trajan's Dacian campaigns benefited the Empire's finances through the acquisition of Dacia's gold mines, managed by an imperial procurator of equestrian rank (procurator aurariarum). On the other hand, commercial agricultural exploitation on the villa model, based on the centralized management of a huge landed estate by a single owner (fundus) was poorly developed. Therefore, use of slave labor in the province itself seems to have been relatively undeveloped, and epigraphic evidence points to work in the gold mines being conducted by means of labor contracts (locatio conductio rei) and seasonal wage-earning. The victory was commemorated by the construction both of the 102 cenotaph generally known as the Tropaeum Traiani in Moesia, as well of the much later (113) Trajan's Column in Rome, the latter depicting in stone carved bas-reliefs the Dacian Wars' most important moments. Nabataean annexation In 106, Rabbel II Soter, one of Rome's client kings, died. This event might have prompted the annexation of the Nabataean Kingdom, but the manner and the formal reasons for the annexation are unclear. Some epigraphic evidence suggests a military operation, with forces from Syria and Egypt. What is known is that by 107, Roman legions were stationed in the area around Petra and Bosra, as is shown by a papyrus found in Egypt. The furthest south the Romans occupied (or, better, garrisoned, adopting a policy of having garrisons at key points in the desert) was Hegra, over south-west of Petra. The empire gained what became the province of Arabia Petraea (modern southern Jordan and northwest Saudi Arabia). At this time, a Roman road (Via