Complex sentence: In each of these units there was a large central town that was fortified and held 5-6,000 people, and the surrounding hills and valleys were filled with many more mocambos of 50 to 100 people.
Split into simpler sentences: In each of these units there was a large central town that was fortified and held 5,000-6,000 people. The surrounding hills and valleys were filled with many more mocambos of 50 to 100 people.