Political map of Europe & the Mediterranean summer 257 (Gothic Black Sea Raids): In the mid 250s the Goths pressured the Bosporan Kingdom to provide them with ships, which they then used to mount raids across the Black Sea. After initial attacks on Colchis and Trapezus (Successianus), these newly seaborne invaders moved on to sack the rich cities of Bithynia (Goths#3rd century raids on the Roman Empire), while Valerian (Valerian (emperor))—preoccupied with the Persian threat—stood by helplessly.