A recent study of Gian Pietro Carafa's diplomatic career reconsidered the influence he had over the Roman Catholic Church, especially regarding the Catholic Reformation and Counter Reformation.
The EU-funded project CARAFAMCP (The origins of the Roman Inquisition reconsidered: The diplomatic career of Gian Pietro Carafa in England and Spain (1513-19)) was set up to review available knowledge on his early career, before he became Pope Paul IV in 1555.
Further details: The role of Gian Pietro Carafa in the Roman Catholic Church and Roman Inquisition