 As early as the 240s , Odaenathus inflated the Palmyrene army , recruiting the desert nomads and increasing the numbers of the Palmyrene heavy cavalry units ( <unk> ) . In 252 , Persian emperor Shapur I started a full @-@ scale invasion of the Roman provinces in the east . During the second campaign of the invasion , Shapur conquered Antioch and headed south where his advance was checked in 253 by Emesa 's priest king <unk> <unk> . The events of 253 were mentioned in the works of the sixth century historian John Malalas who also mentioned a leader by the name " <unk> " inflicting a defeat upon the retreating Shapur near the Euphrates . " <unk> " is probably identical with Odaenathus , and while Malalas ' account indicate that Odaenathus defeated the Persians in 253 , there is no proof that the Palmyrene leader engaged Shapur before 260 and Malalas ' account seems to be confusing Odaenathus ' future actions during 260 with the events of 253 . 
