Germany doesn't have Prime Ministers, they have Chancellors, but the word they would use to describe other countries is:
Bundespräsident - President
The German prime minister carries the title of "Kanzler"(Chancellor).
The chancellor, not prime minister, is Angela Merkel.
Angela Merkel was the Prime Minister of Germany in 2013.
The noun prime minister is a singular, common, compound noun; a general word for a position or title; a word for any prime minister anywhere.The noun prime minister is a proper noun when used as a specific title, such as David Cameron, British Prime Minister or the office of Prime Minister of France.
Deputy prime minister is a subaltern of prime minister.
Hitler became chancellor (German equivilent to prime minister) in 1933
Hitler was appointed Chancellor (the German equivalent of Prime Minister) in January 1933.
chancellor, premier, prime minister , the person who is head of state
The German Head of State is Germany's Prime Minister Christian Wulff.
The compound noun 'prime minister' is capitalized only when it is a proper noun as a specific title such as the Prime Minister of India, or a specific person such as Prime Minister Stephen Harper (Canada).