Chapter 19 is the first of two chapters that examine the previous history of the families of leading figures of the Trojan War, in this case the brothers Agamemnon and Menelaos, who led the Greek army, and the cousins Achilles and Ajax (Aias), who were the most formidable warriors on the Greek side. The first part of the chapter thus provides an account of the early history of the Pelopid family, which was descended from Tantalos, king of Lydia. Achilles and Ajax for their part belonged to the Asopid family, whose history is recounted in the second part of this chapter, particularly their branch of it that was descended from Aiacos, king of Aegina. The chapter concludes with a brief survey of the other branches of the Asopid family.