» For the U.S. area code, see Area code 425. 400s | dp1=410s | d=420s | dn1=430s | dn2=440s | dn3=450s }} Events By Place Western Roman Empire October 23 — Valentinian III becomes Western Roman Emperor. Aëtius leads an army into Italy to support the self-proclaimed emperor Joannes. Galla Placidia becomes a regent for her son. Eastern Roman Empire The Sanhedrin's disbanded by the Roman Empire. By Topic Arts and Sciences Last known usage of Demotic. c. 425-426 - Mausoleum of… (More on 425)