Complex sentence: The Old World consists of those parts of Earth known to Europeans, Asians, and Africans in the 15th century; it includes Europe, Asia, and Africa (collectively known as Afro-Eurasia), plus surrounding islands.
Split into simpler sentences: The Old World consists of those parts of Earth known to Europeans, Asians, and Africans in the 15th century. The "Old World" includes Europe, Asia, and Africa (collectively known as Afro-Eurasia), plus surrounding islands.