Within the Indo-European language tree, Dutch is grouped within the Germanic languages, which means it shares a common ancestor with languages such as English, German, and Scandinavian languages. All Germanic languages are united by subjection to the sound shifts of Grimm's law and Verner's law which originated in the Proto-Germanic language and define the basic differentiating features from other Indo-European languages. This assumed to have originated in approximately the mid-first millennium BCE in Iron Age northern Europe.