Ovid got exiled to Tomis, modern Constanta, on the Black Sea, near where
the Danube pours into it.
Hister
congelat et tectis in mare serpit aquis;
quaque rates ierant, pedibus nunc itur, et undas
frigore concretas ungula pulsat equi;
perque nouos pontes, subter labentibus undis,
ducunt Sarmatici barbara plaustra boues.
(Tristia 3)
(The Danube freezes and crawls to the sea with its waters hidden; and
where boats had gone, feet now go and horses' hooves beat the cold-
hardened waves; and over new bridges (waters flowing below) Sarmatian
oxen draw barbarian carts.)
The Danube still freezes;
https://goo.gl/E1hRWV
Ed