In Deuteronomy 19:14, we read that there were landmarks, "which they of old time have set in thine inheritance".
Thou shalt not remove thy neighbour’s landmark, which they of old time have set in thine inheritance, which thou shalt inherit in the land that the Lord thy God giveth thee to possess it.
I know that this verse is often used as one of many speaking against moving or removing landmarks set by the neighbor to separate one's own inheritance from the next, but the KJV for this verse doesn't seem to say that here (other verses do).
It would appear that this verse suggests that there were landmarks already set in the Promised Land, set there prior to the time that Moses was speaking, which would be inside the inheritances of individuals. I understand that moving things which people consider to be border to their land would be unwelcome (if someone moves my fence [put up by me] or the road [set up before my time] to make my yard smaller and theirs bigger, I might have words with them), but if that landmark weren't a border marker (like a koi pond in my backyard, the guy who lived here before me thought was awesome and is now a drowning hazard for my kid), this verse seems to say that the Children of Israel weren't allowed to move or remove landmarks in their backyard.
My questions are: 1. What sort of landmarks were being referred to here, 2. Can I understand "they of old time" as referring to people who lived before Moses, people who were not in the family of Abraham (which landmarks would be seen as sacred anyway, without this commandment), and 3. Why was this commanded?
Now, #3 is probably severely off topic for this site, but if so number 1 and a confirmation of 2 should give me sufficient background to answer 3 myself.
Or perhaps I should ask if the KJV (or its source text) translated poorly, and the various commentaries quoted here are correct that "they of old time" refer to people who lived generations after, not prior to, Moses and his listeners.