Wiktionary
adv. 1 With someone's favour or blessing. 2 Without interruption. In tranquility. peacefully.
Usage examples of "in peace".
For a time the repairs went on in peace under the immediate protection of these two airships.
He played Chutes and Ladders with her last night, so she's fallen in love with him and won't leave him in peace.
Better to deal in peace with such strength, if it could be done without offending the tribe's guardian gods.
Beyond the clear glass of the window wall, the lands around Livermore spread away in peace and silence.
Now we can return home in peace, without having to fear the stranger at our thresholds.
The Baron was apparently unarmed, perhaps as an indication that he came in peace.
Our brothers get along together-you've seen us, you've shared-live in peace and happiness with no bitterness, no jealousy.