Let me edit my own answer in a new post, as it doesn't add up 
This means thatone two persons see one silver and one gold crown, which means they still don't know a thing. That leaves the one person who sees gold only, he knows he is wearing silver. Hence he anounces: Iwear silver on my head and becomes minister.
Username: Loyce
Q. An emperor wants to find the cleverest of all men in his country to appoint him as his minister. There were three who made it to the last. The emperor places a crown on each of their heads, such that each man could see all of the other crowns, but none their own. Each crown was either gold or silver. The emperor gave his word to the wise men that at least one of them was wearing a gold crown; and that the contest would be fair to all three men. They were also not allowed to speak to each other. The emperor declared that whoever stood up and correctly announced the color of his own crown first would become his new minister. The men sat for a very long time before one stood up and correctly announced the answer. What did he say, and how did he figure it out?
If someone would see two silver crowns, he would know he wears gold. This didn't happen, as they sat for a very long time, which means there are at least two golden crowns.This means that
Username: Loyce