Royal Decree is a rare Enchantment card from Alliances (ALL), collector number 14. Current market price: $0.73, TCGplayer market prices via Scryfall.
Cumulative upkeep {W} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.) Whenever a Swamp, Mountain, black permanent, or red permanent becomes tapped, this enchantment deals 1 damage to that permanent's controller.