Complex sentence: The Swazi settlers, then known as "the Ngwane" (or "bakaNgwane"), before entering Swaziland had been settled on the banks of the Pongola River and prior to that in the area of the Tembe River near present day Maputo.
Split into simpler sentences: The Swazi settlers, then known as "the Ngwane" (or "bakaNgwane"), before entering Swaziland had been settled on the banks of the Pongola River. Prior to that they were settled in the area of the Tembe River near present day Maputo.