they stray from the facts or take creative liberties.

In this case, they based the series on Lockhart's book. He actually appears in the series, as an agent working with Reilly. I've read suggestions that the book may be a highly romanticized version of events. The series probably took liberties with the book...so there you have it. Still, as I watched I was able to trace world events as I understood them from my own readings. What came through for me, more than anything, was the cynicism. People are pieces on a chess board. Their lives meant nothing.

I just looked it up. Lockhart's book is available, free, on Internet Archive. I think I'll give it a quick read.

Memoir of a British Agent