In 1270, the solicitor of the senate of Hamburg, Jordan von Boitzenburg, wrote the first description of civil, criminal and procedural law for a city in Germany in the German language, the Ordeelbook (Ordeel: sentence).
In 1529, the city embraced Lutheranism, and it received Reformed refugees from the Netherlands and France.
The first bishop, Ansgar, became known as the Apostle of the North.
The official name reflects Hamburg's history as a member of the medieval Hanseatic League, a free imperial city of the Holy Roman Empire, a city-state, and one of the 16 states of Germany.
Before the 1871 Unification of Germany, it was a fully sovereign state.
This charter, along with Hamburg's proximity to the main trade routes of the North Sea and Baltic Sea, quickly made it a major port in Northern Europe.
Its trade alliance with Lübeck in 1241 marks the origin and core of the powerful Hanseatic League of trading cities.
Hamburg has an oceanic climate (Cfb), influenced by its proximity to the coast and marine air masses that originate over the Atlantic Ocean.