Complex sentence: The Middle kingdoms of India had already the largest economy of the ancient and medieval world, the Napata/Meroitic kingdom extended over the current Sudan and Ethiopia, the Olmecs controlled central Mexico and Guatemala, and the pre-Incan Chavín people managed large areas of northern Peru.
Split into simpler sentences: The Middle kingdoms of India had already the largest economy of the ancient and medieval world. The Olmecs controlled central Mexico and Guatemala, and the pre-Incan Chavín people managed large areas of northern Peru.