Nuremberg, known as Nürnberg in German, dates back to the Middle Ages when it was first established as a royal residence. The city quickly flourished into a thriving trade center, becoming one of the most important cities in the Holy Roman Empire. Nuremberg's rich history includes its role as the unofficial capital of the Empire, hosting the Imperial Diets, and the birthplace of the famous artist Albrecht Dürer. During the 20th century, it was infamous for the Nuremberg Trials, a series of military tribunals held after World War II to bring Nazi war criminals to justice.