| the western portion of the Roman Empire after its division, a.d. 395, which became extinct a.d. 476. |
| Western Empire or Western Roman Empire The western section of the Roman Empire, first set apart in A.D. 286 by Emperor Diocletian and later (395) formalized after the death of Theodosius I. It comprised Italy, Spain, Gaul, Britain, Illyricum, and northern Africa and lasted until 476. |