Scarrow Simon. The Eagle in the Sand

Vol. VII of the historical fiction series 'The Eagles' (2006).
Trouble is brewing on the eastern frontier of the Roman Empire. The troops are in a deplorable state, while the corrupt behaviour of the their senior officers threatens to undermine the army's control of the region. To restore the competence of the men defending a vital fort, two experienced centurions are dispatched to Judaea from Rome.
On their arrival Macro and Cato discover that there is even more serious problem to deal with. Bannus, a local tribesman, is brewing up rebellion amongst the followers of Jehoshua, who was crucified in Jerusalem some seventeen years earlier. Now Bannus is pushing the faction towards violent opposition to Rome.
As the local revolt grows in scale, Rome's long-standing enemy Parthia is poised to invade. Macro and Cato must stamp out corruption in the cohort and restore it to fighting fitness to quash Bannus - before the eastern provinces are lost to the Empire forever.