In Augustus' capacity as supreme head of the public road system, he converted the temporary cura of each of the great roads into a permanent magistracy. The persons appointed under the new system were of senatorial or equestrian rank, according to the relative importance of the roads respectively assigned to them. It was the duty of each curator to issue contracts for the maintenance and repairs of his road, and to see that the contractor who undertook the work performed it faithfully, both as to quantity and quality. Moreover, he authorized the construction of sewers and removed obstructions to traffic, as the aediles did in Rome.[8] It was in the character of an imperial curator, though probably of one armed with extraordinary powers, that Corbulo (as has been already mentioned) denounced the magistratus and mancipes of the Italian roads to Tiberius.[8] He pursued them and their families with fines and imprisonment for 18 years (21-39), and was rewarded with a consulship by Caligula, who was himself in the habit of condemning well-born citizens to work on the roads. It is noticeable that Claudius brought Corbulo to justice, and repaid the money which had been extorted from his victims.