Rights and wrongs

For the thesis I am using Brian Tierney's The Idea of Natural Rights and Annabel Brett's Liberty, Right, and Nature. One of the questions I will try to answer in the thesis is whether Aquinas's account of ius is compatible with notions of 'passive' and 'active' rights. My suspicion at the present moment is that they are not. Ius may be derived from lex in a certain way, but it is not yet clear to me if lex is just a determination of reason on what is to be done, or whether it in turn is dependent upon something more basic.

Tierney's and Brett's books have been useful; other authors who have written on rights include Quentin Skinner, Richard Tuck, and Ian Shapiro. While there may be a connection between the medievals and the Renaissance and modern theorists of right (plus the Spanish scholastics), it would be too much work for me to look at all of the prominent theorists plus their sources. At the congress I discovered Manlio Bellomo's The Common Legal Past of Europe, 1000-1800, published by CUA Press--this book should prove to be useful for the thesis. Civil and canon law may have made use of the word ius in a way that Aquinas acknowledges but does not explain within the Summa Theologiae, that is ius as an active right. What are the roots of this usage? Roman law?

My suspicion is that the use of ius as an active right, even though it may be tied up to the permissive function of law, is dominant because of voluntaristic understandings of freedom, which is a perennial error given the fragility of human moral development. But that's just a guess for now...