The problem was that females were viewed as not having the strength of person to rule a country. There was never any legal coding to determine whether women could or couldn't inherit, though precedents had to be respected. England didn't follow Salic Law so it didn't rather prevent the line of succession passing through female blood. In fact I believe I remember there being a case saying that Salic Law originally was cognatic primogeniture (women can inherit if there is no male heir) but the French argued that it actually should be interpreted saying that the line of succession can never pass through a woman in order to prevent Edward III from being their legal heir in 1337, leading to a change in understanding of the law. But back on course. The precedent for succession through female blood was established all the way back in what was it? 1135 I think, where Henry I had the English Barons accept his daughter Matilda as his heir. Yes, she faced a civil war over it, but the point had been made and the civil war was only ended by a settlement whereby the two rival claimants were tied through marriage to each other (Stephen's son Geoffrey to Matilda iirc) and I think which made Matilda Stephen's heir. After that, it was accepted that women could inherit provided that no male heir existed, as was expected.