After the farmers attempt to retake the Animal Farm, the victorious animals create two military medals, "Animal Hero, First Class," and "Animal Hero, Second Class." Snowball and Boxer receive the first for their efforts in routing the humans, while a sheep killed in action receives the second. However, when Snowball is expelled from the farm, the medals become a tool of propaganda instead of a genuine honor. Napoleon promises a medal and apples to any animal who can bring Snowball in. Later, he adopts both medals himself:
Napoleon emerged from the farmhouse, wearing both his medals (for he had recently awarded himself 'Animal Hero, First Class,' and 'Animal Hero, Second Class'), with his nine huge dogs frisking round him and uttering growls that sent shivers down all the animals' spines.
(Orwell, Animal Farm, george-orwell.org)
This is standard behavior for dictators, who often never serve in a military capacity but still promote themselves to General and appear in public with many distinguished medals. By giving himself the medals, which are remembered for their original meaning by the animals, Napoleon takes on a history of courage and responsibility that he has not earned, and also keeps any other animal from seeking to earn higher honors than himself.
The two military decorations was Animal hero first class,which Snowball and Boxer earned (it was a brass medal which they could wear on sundays and holidays),while the other decoration was Animal hero second class which was awarded to the dead sheep.