cdli Fifth-century date 451, in old Rome Middle of the fifth century CMII divided by II 451, to Nero One-fifth of MMCCLV Nero's 451 451, to Caesar A year in the life of Attila Year Attila was defeated in Gaul Year Attila invaded Gaul Fifth-century year Mid fifth-century year Date when the Hun was on the run Year in the life of St. Patrick