The scale of this passage at first seems to be about some tension between public and private law, but then the rest of the passage goes on to discuss how women at that time could have powerful public roles. Thus, the scale--a heavily weighted one--is that 13th century English women could have public power (through land control) vs. those women did not have public power.
P1: introduce common belief and counter thesis: common view is that 13th century women should be looked at only through public lens, but actually they could control land and thus had public power.
P2: explain mechanism to support thesis: how women controlled land
P3: implications: women controlling land --> women had public power