Treaty of Eternal Peace

Pacification (Whenever a creature enters the battlefield under an opponent's control, put a +1/+1 counter on it.)
Whenever one or more +1/+1 counters are put on
a creature your opponent controls, put a peace counter on Treaty of Eternal Peace.
At the beginning of your upkeep, if there are 15
or more peace counters on Treaty of Eternal Peace, you win the game.