St. Augustine of Hippo was Manichean before he became a Christian. I have read in Wikipedia that Mani, the prophet of Manichaeism, knew but rejected the doctrines of Buddha and that he died about a century before St. Augustine. There's also in Wikipedia information about Indian, maybe Buddhist, ambassadors and travelers arriving to Rome and Greece.
Is there any evidence to show that St. Augustine or some other common westerner Roman from his time (about 400 AD) was familiar with Buddha and his teachings? I want to exclude eastern Romans, like Syrians and Egyptians, from this question. When I say "common Roman" I mean ordinary, maybe educated people, like Augustine. I exclude politicians, merchants and ambassadors.