though established only relatively recently (1212), the poor clares already had a mitigated form of their rule, approved by pope urban iv, which allowed the order to own property, as opposed to the restrictions originally laid down by the foundress, clare of assisi. the precise calibrated formulation of these matters is referred to as the isabella rule, after the sister of louis ix of france (st louis), st isabella, who though never a nun had in 1256 founded the poor clares' abbey of longchamp in part of the forest of rouvray (now the bois de boulogne), west of paris.