A quick story from Songling Pu:
Formerly, when the Dutch were permitted to trade with China, the officer in command of the coast defences would not allow them, on account of their great numbers, to come ashore. The Dutch begged very hard for the grant of a piece of land such as a carpet would cover; and the officer above-mentioned, thinking that this could not be very large, acceded to their request. A carpet was accordingly laid down, big enough for about two people to stand on; but by dint of stretching, it was soon enough for four or five; and so they went on, stretching and stretching, until at last it covered about an acre, and by-and-by, with the help of their knives, they had filched a piece of ground several miles in extent.
I believe I first heard this story about a woman who bargained for a oxhide of space to build her nunnery, but I’ve seen variants in other places. I recall a king who bargained this much land with the vikings, as another example.
It makes a fine covenant origin story: your ancestors bargained for space to unfold a picnic blanket and, as it happens, it reached from from the top of the hill all the way to the river. Your covenant has many fine spinners in it, and has a festival each year to celebrate the blanket. You carry it about during the Aegis of the Hearth ritual and sometimes check its memories for point s of covenant history. The design on the blanket is like a battle tartan for your grogs.
In Ars Magica, we have supernatural realms which bargain with mortals, either wanting land or giving it away. A demon who asks enough land to bury one of his servants: just enough for his shroud and no more. A faerie who seeks enough land for the hooves of his horse, and no extra. Magi who seeks enough of a church’s lands to raise a beacon fire. Magi who deal with a faerie court, for as much land as rests in the shadow of a coin.
I used to try and pull these stories back in university, but one of my players was studying law and pointed out that lacking a meeting of them inds there is no contract. I’m not sure if this is true of medieval laws, in various places, but it certainly seeme effective with faeries and, surprisingly, demons. Why demons allows themselves to be tricked has been discussed in various other locations, but, in short, it tempts others to wager with demons if there is a monument ot a demon losing. Also, some of the “losses” were ju7st greater evils in the making: a lot of the Devil’s Bridges have been in the right place to allow conquering armies to cross rivers.
Games From Folktales 