In your scenario the causeway itself might be regarded as a highly potent symbol of power in itself. What more significant exercise of your power could there be than to decree the very route people must walk (or perhaps mustn’t walk, unless specially authorized) and you can order all this from your grave.

I can’t remember whether Machiavelli, in his instruction manual to Princes on how to hang on to power by any foul means they could, discussed post-death tactics, but he should have. I do remember a Trades Unionist discussing his philosophy of effective leadership, which was “If you get ‘em by the balls their hearts and minds will follow shortly…” It’s pretty clear that any leader would have a vested interest in extending his hold over his people to beyond the grave- both to preserve his dynasty and also, in life, to leave no room for dangerous democratic thoughts to take root.

Barrows = Power? Why not. Why else have them raised rather than flat?…