The storyline is quite captivating but the sex in your face every 13 minutes is aggravating, not titillating.
The music consultant is an unread moron.
The music of JS Bach would not have been known in Spain at that time. The two Bach Minuets played on the Harpsichord were found, after Sebastian's death in a Notebook he had assembled for his 2nd wife, Anna Magdalena.
Domenico Scarlatti was the teacher of the Spanish Infanta and composed for her over 500 keyboard sonatas. He would have been the preeminent Spanish keyboard composer at that time.
As connected to the Spanish Court as the Duke's household was portrayed to be, Scarlatti's Sonatas would not have been hand-copied and shared with women keyboard deletantes unable to tackle them.
The behavior of the Castrato, Farinelli would not have been acceptable, especially since he is shown trying to make a great impression so as to build his career.
This series is beautifully shot but but the story and script has serious holes. It suffers from numerous anachronistic errors and highly unlikely points of plot.