Complex sentence: Előd was the chieftain of the Hungarian "Nyék" tribe, which occupied the region around Lake Balaton, mainly the areas what are known today Zala and Somogy counties.
Split into simpler sentences: Előd was the chieftain of the Hungarian tribe of the "Nyék". The Nyék tribe occupied the region around Lake Balaton, mainly the areas what are known today Zala and Somogy counties.