German citizenship is primarily based on the principle of jus sanguinis. In other words one usually acquires German citizenship if a parent is a German citizen, irrespective of place of birth. A significant reform to the nationality law was passed by the Reichstag (the German parliament) in 1999, and came into force on 1 January 2000. The new law makes it somewhat easier for foreigners resident in Germany on a long-term basis, and especially their German-born children, to acquire German citizenship. The previous German nationality law dated from 1913.