How many times was germany united in its history? when?

Germany has been unified twice in its history. Both times have been relatively recently, with the first one being in 1971 and lasting until 1945, and the second being from 1990 and is still going.

Throughout the history the Germanic people have been divided into numerous tribes, and later into numerous small states. In some occasions they were unifying to defend against some invading force, but that never happened in territorial manner and formation of a single country.

Otto fon Bismarck is the one responsible for the first unification of Germany which happened in 1971, when he managed to unify all the German smaller states into a single German Empire. That lasted until the end of the World War II, as Germany was divided among the Allies who won the war. Germany only managed to unify again in 1990 after the fall of the Berlin Wall, giving birth to the modern day Germany.