 Complete the following phrase:  The poemwhich most speculate proceeded in chronological orderwas likely divided into triads with a concentric, symmetrical structure. In the first seven books, Ennius wrote about mythical and historical past episodes, whereas in the following eight and eventually, eleven, he wrote about contemporary events. Although most of the poem has been lost, there is a traditionalalbeit conjecturedorganization for the book. Books 13 cover the end of the Trojan War in 1184 BC, to the reign of the last king of Rome, Lucius Tarquinius Superbus 535509 BC. Books 46 revolve around the early Roman Republic up until the 