I answered their questions 'to the best of my knowledge'. [=I gave the best answers I could based on what I knew, but I might have answered differently if I had known something else]
No one arrived late 'to my knowledge'. [=I am not aware that anyone arrived late, but it is possible that someone arrived late and I don't know about it]
They went on vacation, 'safe in the knowledge' that the farm would be well cared for while they were away.
(..) Try not to kill too many, we need them alive. Look at you. You haven't aged a bit. The power that must be locked away here, the knowledge. I didn't know so many books even existed. - He sees no one? - The world's been at peace. It would do the Guardian (..)2016 Warcraft