The region properly called by their name, bounded on the south by the Douro and on the east by the Navia, was first entered by the Roman legions under Decius Junius Brutus in 137-136 B.C. (Livy lv., lvi., Epit.); but the final subjugation cannot be placed earlier than the time of Augustus (31 B.C. - A.D.
Clebsch has shown, from purely analytical considerations (Crelle, lvi.); and then = Z d(?G, m), ?