It's no surprise that when time travel appears in a universe where going back in time can alter history, a group appears, (apparently) acting to preserve the continuum they know. But when did science fiction writers begin writing about them?
My most recent experience with the Time Police** is Jodi Taylor's Chronicles of St. Mary's series, but the author I associate this idea with the most is Poul Anderson. His story "Time Patrol" appeared in F&SF in May 1955.
Since these all appeared in 1955, and two authors happened on the same idea in the same year, it might be that the Time Police were already an established idea. So I'm curious if any Time Police stories preceded this, and what was the first.
** No, Herodotus got the idea that there were gold-mining ants in India all by himself, not from me. I deny it categorically.