The vitality of communal societies among the Slavs naturally led to the maintenance of a custom which drew its origin from the solidarity of families, and it is therefore not surprising to find it in Poland described as in full force as late as the eighteenth century, the defendant being obliged to support his purgatorial oath with conjurators, who swore as to its truth.[235] Yet among the Poles confidence in it as a legal proof had long been undermined. In 1368 Casimir III. decreed that a man of good repute, when accused of theft, could clear himself by his own oath; but if his character was doubtful, and compurgation was prescribed, then if he fell short by one conjurator of the number required, he should satisfy the accuser, though he should not be rendered infamous for the future. This led to an increase of crime, and a hundred years later Casimir IV. proclaimed a law by which compurgation was only allowed three times, after which a persistent offender was abandoned to the full severity of the law, as being presumably guilty and not deserving of escape. At the same time any one summoned to compurgation, and appearing before the judge without compurgators, was _ipso facto_ pronounced infamous. From a case recorded it would appear that twelve conjurators were required to outweigh the single oath of the accuser.[236] Among the southern Slavs the custom was likewise preserved to a comparatively late date. An edict of Hermann, Ban of Slavonia, in 1416, orders that any noble accused of neglect to enforce a decree of proscription against a malefactor, should purge himself with five of his peers as conjurators, in default of which he was subject to a fine of twenty marcs.[237]