There is an interesting post by New Catholic at the Rorate Caeli website which is a translation of an article by Roberto de Mattei about the theological factions within the College of Cardinals in the 1550s and 1560s, including the allegations of heresy or error brought against the English Cardinal Pole.
The article can be read at Paul IV and the Heretics of His Time
The text of Pope Paul IV's Bull Cum ex Apostolatus Officio, referred to in the article, can be read in translation here.
There is an online account of the Pope at Pope Paul IV, and of one of the other principal figures in the article which can be read at Giovanni Morone.
Pope Paul IV
In recent years there has been quite an amount of academic work done on Pole, with at least two biographies, and a re-evaluation of his achievements as Legate and Archbishop in the reign of Queen Mary I. The Mattei article gives the Roman context for the pressing issues facing the respective Popes and Cardinals in these decades, and the more general point as to how to address suspicions of heresy at the heart of the Church.
Cardinal Reginald Pole