This episode depicts the marriage of George Boleyn and Jane Parker. In fact they were married in 1524 or 1525, some ten years before this episode takes place.
In this episode and several subsequent ones, Master Mark Smeaton is shown playing a modern violin. The equivalent stringed instrument in Tudor times was the viol, played differently from a violin, and shaped differently. The bow with which is was played was also shaped differently to the one shown here (clearly a modern bow).
Cromwell shows George Boleyn a printing press and George reacts like this something very new. However, the first printing presses came to London in 1480, more than 50 years earlier.
During the play as commissioned and produced by Cromwell, there was a character that is to represent France or Francis I, with his face painted in the tricolour flag of modern France. Although it is probably done in that fashion for modern viewers to recognise, but the tricolour will not come into existence until the French Revolution 255 years later.
As SFX footage of Rome is shown, it depicts an already finished Basilica of St. Peter. While the foundations have been laid some years before Henry VIII took the throne, the great church was still being built throughout his reign. Henry died in 1547, and St Peter's basilica wasn't finished until the end of the 16th Century (the dome itself was only finished by 1590, and the entire church by 1626). The footage clearly shows the basilica in much the same shape as it is today, while it should be only partly finished and surrounded by scaffolding, ramps, cranes; and the square in front would sooner be filled with workmen rather than worshipers.
Anne tells Mark Smeton that the French admiral had been in England for two weeks and had not acknowledged her. She then says "I mean, can you imagine?" Which someone in 16th century England would not say and more something from the 21 century.