Royal Weapon (5e Equipment)

Weapon (any weapon), rare (requires attunement)

Royal weapons are magical items with marvellous decorations and inscriptions given to royalty and their followers as a sign of loyalty and honor.

You gain a +2 bonus to attack and damage rolls with this magic weapon. To attune to a royal weapon, you must be deemed worthy by the weapon's previous owner or by the leader of the previous owner's nation. If you make an attack with a royal weapon when you aren't attuned to it, you have disadvantage on the attack roll.
While attuned to this weapon, you gain proficiency with the Persuasion skill. If you were already proficient in the Persuasion skill, you add double your proficiency bonus instead of your normal proficiency bonus to checks made using that skill.