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.
(..) I am Unferth, son of Ecglaf. - Unferth, son of Ecglaf? I know who you are. They say you killed both of your brothers when you witness them having knowledge of your mother. I have another true thing to tell you, Unferth Kin-Slayer. If your strength and heart was as strong and fierce as your words, (..)2007 Beowulf