He had first - hand knowledge of the disease .
Was present in Rome when it first struck in 166 AD , and was also present in the winter of 168 -- 69 during an outbreak among troops stationed at Aquileia .
He had first - hand knowledge of the disease , and was present in Rome when it first struck in 166 AD , and was also present in the winter of 168 -- 69 during an outbreak among troops stationed at Aquileia .