Who introduces the idea of the revolution to the animals?

The idea of the revolution is introduced to the animals by Old Major, a prize-winning boar in George Orwell's "Animal Farm." He shares his vision of a rebellion against human oppression during a meeting with the animals, urging them to unite and overthrow their human owner, Mr. Jones. Old Major's speech inspires the animals to consider the possibility of a better life free from human tyranny. His thoughts lay the foundation for the subsequent revolution and the establishment of Animalism.