It is generally assumed that the name Himmerland is derived from the tribe of the Cimbri since, in the Geography of Ptolemy (2nd century AD), the Kimbroi (in GreekΚίμβροι) are located in the northernmost part of the peninsula of Jutland, called Kimbrikē chersonēsos in Greek (Κιμβρική Χερσόνησος). The Latin c and Greek k attest an earlier stage of Germanic in which the Germanic sound shift was not yet completed (*k > *χ > h), or it has been assumed the Latin form may be derived through Celtic which substituted ch for h (Germanic *himbr-, Celtic *chimbr-, Latin cimbr-). If Cimbri (similar to the Welsh word for themselves ‘Cymry’ from ‘combrogi’ - fellow countrymen) were related to other Celtic tribes, the first part of Himmerland might be related in name to the Humber estuary.[citation needed]