Complex sentence: From the 18th century onwards, however, the Hadza came into increasing contact with farming and herding people entering Hadzaland and its vicinity from elsewhere; their interaction with these peoples were often hostile and caused a period of population decline in the late 1800s.
Split into simpler sentences: From the 18th century onwards, however, the Hadza came into increasing contact with farming and herding people entering Hadzaland and its vicinity from elsewhere. Their interaction with these peoples were often hostile and caused a period of population decline in the late 1800s.