Historian's Wisdom 

Enchantment — Aura
Enchant artifact or creature When this Aura enters, if enchanted permanent is a creature with the greatest power among creatures on the battlefield, draw a card. As long as enchanted permanent is a creature, it gets +2/+1.
Legality
standardNOT LEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL