a monument erected not -earlier than the time of
Severus (AJA 1909, 186
) on the north end of the hemicycle of the ROSTRA
(q.v.), and mentioned only in later literature (Not. Reg. VIII; Eins.
I. 5; 7. 7; 8. 8; DAP 2. ix. 389). It is now a cylindrical brick-faced
core, rising in three stages, with a diameter of 4.60 metres at the bottom
and 3 at the top, but originally it was covered with marble. It represented
the central point of city and empire, probably in imitation of the ὀμφαλός
in Delphi and other Greek cities, and may have corresponded
architecturally to the MILLIARIUM AUREUM
(q.v.) at the south end of
the hemicycle (Jord. i. 2
. 245; HC 80; Thedenat 134, 233).