Paulus Vladimiri, a 15th century Polish canon lawyer and university rector, showed that the Catholic understanding of human dignity and human rights was broader and deeper then than among the Protestants in the next century.
Most of his works have been translated. They aren’t easy to get, however, and they are in the form of consilia - paid legal opinions.
It may be the case that Catholic scholars of the 15th century were ahead of Protestant scholars in the 16th (such as they were), but if Catholics had an early lead they did not hold it long. Needless to say, it is in Locke that the concept of unalienable rights reached a mature development.
More importantly, it is an empirical fact that Protestant countries have been more (small d) democratic and capitalistic than Catholic countries. There are a lot of attempts to explain this, and none of them are very satisfying (see also: Max Weber's failed thesis). But the empirical fact remains: Protestant countries took over the cultural lead from Catholics. This is still true today: the United States is the only industrialized country that has not secularized (in fact, it is heading the other direction).
Interesting post. Bumping to myself to research later.