Ambassador Chapuys

"yes and so much of what has been written by historians about this time is based on the Historical Chapuys' letters and he was a pivotal character because he represented spain's catholic influence on the court factions in Henry's time. He was fiercely pro-Katherine/Mary and anti-Anne and subsequently influenced Jane to some extent.

Its interesting though what Retha Warnicke said about the information he provides about the time :

"A close reading of the Ambassador's correspondence between 1529 and 1536 readily indicates that his information should be divided into at least the following four categories;
(1) repetition of ubiquitous rumors at court
(2) information deliberately leaked to him by royal servants
(3) original and sometimes unsubstantiated speculation of his own
(4)actual first-hand information such as interviews with the king and his ministers, announcements of arrivals and departures of envoys and seasonal movements of the court.
Often it is extremely difficult to decide into which of the first 3 categories the gossipy, second-hand news should fall, a difficulty that must alert scholars to the need for handling of his letters with caution."

- Retha Warnicke in her introduction to her book, The Rise and Fall of Anne Boleyn"