Question: where was rome founded and what natural defences aided its position

title: History of the Roman Empire
text: For the moment , however , there was another concern . The death of Valens left Gratian and Valentinian II as the sole Augusti . Gratian was now effectively responsible for the whole of the Empire . He sought a replacement Augustus for the Eastern Roman Empire . His choice was Theodosius I , son of formerly distinguished general Count Theodosius . The elder Theodosius had been executed in early 375 for unclear reasons . The younger was named Augustus of the Eastern Roman Empire on January 19 , 379 . His appointment would prove a deciding moment in the division of the Empire .