Faced with the need to organize their growing number of conquered territories, the Romans soon developed a standardized system of farmland division which could be adapted to the various geographical contexts present on the Italian peninsula. The centuriae were rectangular allotments with an area of 200 iugeri (about 50 hectares), which corresponded to 100 heredia – the allotments first granted to Roman citizens and which were traditionally attributed to Romulus. They were arranged along the decumani and cardines orthogonal axes marked out by a groma or a mensor (land surveyor) by means of a groma driven into the ground. Each centuria could be assigned to one or more people in the establishment of a colony, as part of a policy of wealth redistribution or to contain social tensions – one example of this being the extensive centuriation ordered by the Gracchi in the second half of the Second Century BCE. Many boundary inscriptions on stone markers survive, testifying to the major scale on which this redistribution activity was conducted under the Republic. Traces of this agrarian reorganization have emerged in aerial photography and satellite images, in which it is possible to discern the water channelling systems and even the outlines of the fields themselves, particularly in areas where there was little activity in the centuries that followed.