On July 10, 1509, John Calvin was born in France. After breaking with Rome during the Reformation, he moved to Switzerland, from where he published the classic "Institutes of the Christian Religion." This work is arguably the first Protestant attempt at systematic theology, and his thoughts are still influential today -- and that influence seems to be on the rise. Everywhere you look, especially online and in the podcast world, Calvinist theology is dominat.
I personally appreciate the fact that Calvin was able to separate his disapproval of Roman Catholic mariology, from his positive view of Mary herself, and that he did not hold to a number of the Protestant views on her that became common after the Reformation.
The quincentenary is being observed around the globe with the Geneva-based World Alliance of Reformed Churches acting as a central organizer of "Calvin 09."